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  • Lehtoranta, Liisa (Helsingin yliopisto, 2012)
    Viral respiratory and gastrointestinal infections are a major health problem, in particular among children. A large range of etiologic agents and increasing antiviral and antibiotic resistance, challenge the development of efficient therapies. Accumulating evidence suggests that specific probiotic bacteria are able to decrease the risk and symptoms of these infections. This thesis investigated the effects of specific probiotics, in particular Lactobacillus rhamnosus GG, on respiratory and gastrointestinal virus infections in a cell model in vitro, in a rat model in vivo, and in children. A particular focus was on questions, whether viability of a probiotic is an important factor in probiotic-virus interaction, and whether a combination of probiotics is more effective than single strains. A novel colorimetric neutralization assay was developed for measuring influenza virus antibodies in human sera. The method was applied to measure antibody response after the administration of a seasonal, inactivated, trivalent influenza vaccine. The results were compared with those obtained with a traditional hemagglutinin inhibition test. The results obtained with both assays correlated well. Moreover, neutralization test proved to be more sensitive and specific than the hemagglutinin inhibition test. Thus, the method is valid for influenza virus research, and it could be applied for studying immune adjuvant effects of probiotics on serum influenza antibody titers in the future. Immunomodulatory effects of probiotics were screened in human macrophage model in vitro. After 24 hours of bacterial stimulation, probiotic combination of L. rhamnosus GG and L. rhamnosus Lc705 was not able to significantly induce higher macrophage cytokine and chemokine production (TNF-α, IL-1β, IL-6, IL-10, and IL-12, MCP-1, IP-10) over individual L. rhamnosus strains. However, cytokine responses induced by this combination were stronger than responses induced by traditional starter culture bacterium Lactococcus lactis ARH74, highlighting that immunomodulatory effects of probiotics are strain specific. The effects of viable and unviable L. rhamnosus GG in rotavirus infection were investigated in a neonatal rat model. Consistency of feces, animal weight, colon weight and the rotavirus colonization of plasma and intestinal tissues were considered as indexes of infection severity. Nonviable L. rhamnosus GG had beneficial effects in rotavirus infection in terms of reducing rotavirus induced body weight reduction and colon weight increase. However, viable L. rhamnosus GG was more effective in reducing significantly viral load in the gastrointestinal tract. The effects of L. rhamnosus GG alone or probiotic combination containing L. rhamnosus GG on the occurrence of viral respiratory infections was assessed in a six month intervention trial in children or in otitis-prone children. Children receiving only L. rhamnosus GG had fewer days with respiratory tract symptoms during the intervention period. However, L. rhamnosus GG did not reduce viral occurrence in the nasopharynx, suggesting that L.rhamnosus GG is able to reduce respiratory virus symptoms through enhancing immune response. In otitis-prone children, L. rhamnosus GG in a combination with L. rhamnosus Lc705, Bifidobacterium breve 99, and Propionibacterium freudenreichii ssp. shermanii JS significantly reduced human bocavirus load in the nasopharynx three to six months after intervention. In conclusion, probiotics and their combinations differ in their ability to elicit immunomodulatory effects in vitro. Viability of a probiotic is an important factor in virus infection. The probiotic L. rhamnosus GG reduced days with respiratory tract symptoms. In children, L. rhamnosus GG alone was not effective in reducing viral occurrence in the nasopharynx. However in otitis-prone children, L. rhamnosus GG in a combination reduced the numbers of human bocavirus.
  • Hatakka, Katja (Helsingin yliopisto, 2007)
    Infectious diseases put an enormous burden on both children and the elderly in the forms of respiratory, gastrointestinal and oral infections. There is evidence suggesting that specific probiotics may be antagonistic to pathogens and may enhance the immune system, but the clinical evidence is still too sparce to make general conclusions on the disease-preventive effects of probiotics. This thesis, consisting of four independent, double-blind, placebo-controlled clinical trials, investigated whether Lactobacillus GG (LGG) or a specific probiotic combination containing LGG would reduce the risk of common infections or the prevalence of pathogens in healthy and infection-prone children and in independent and institutionalised elderly people. In healthy day-care children, the 7-month consumption of probiotic milk containing Lactobacillus GG appeared to postpone the first acute respiratory infection (ARI) by one week (p=0.03, adjusted p=0.16), and to reduce complicated infections (39% vs. 47%, p<0.05, adjusted p=0.13), as well as the need for antibiotic treatment (44% vs. 54%, p=0.03, adjusted p=0.08) and day-care absences (4.9 vs. 5.8 days, p=0.03, adjusted p=0.09) compared to the placebo milk. In infection-prone children, the 6-month consumption of a combination of four probiotic bacteria (LGG, L. rhamnosus LC705, Propionibacterium freudenreichii JS, Bifidobacterium breve 99) taken in capsules appeared to reduce recurrent ARIs (72% vs. 82%, p<0.05; adjusted p=0.06), and the effect was particularly noticeable in a subgroup of children with allergic diseases (12% vs. 33%, p=0.03), although no effect on the presence of nasopharyngeal rhinovirus or enterovirus was seen. The 5-month consumption of the same probiotic combination did not show any beneficial effects on the respiratory infections in frail, institutionalised elderly subjects. In healthy children receiving Lactobacillus GG, the reduction in complications resulted in a marginal reduction in the occurrence of acute otitis media (AOM) (31% vs. 39%, p=0.08; adjusted p=0.19), and the postponement of the first AOM episode by 12 days (p=0.04; adjusted p=0.09). However, in otitis-prone children, a probiotic combination did not reduce the occurrence of AOM or the total prevalence of common AOM pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis), except in the case of children with allergic diseases, in whom probiotics reduced recurrent AOM episodes (0% vs. 14%, p=0.03). In addition, interaction between probiotics and bacterial carriage was seen: probiot-ics reduced AOM in children who did not carry any bacterial pathogens (63% vs. 83%), but the effect was the reverse in children carrying bacteria in the nasopharynx (74% vs 62%) (p<0.05). Long-term probiotic treatment, either LGG given in milk to healthy children for 7 months or a combination of probiotics given in capsules to institutionalised elderly subjects for 5 months, did not reduce the occurrence of acute diarrhoea. However, when the probiotic combination (LGG, L. rhamnosus LC705, Propionibacterium JS) was given in cheese to independent elderly subjects for 4 months, the oral carriage of high Candida counts was reduced in the probiotic group vs. the placebo group (21% vs. 34%, p=0.01, adjusted p=0.004). The risk of hyposalivation was also reduced in the probiotic group (p=0.05). In conclusion, probiotics appear to slightly alleviate the severity of infections by postponing their appearance, by reducing complications and the need for antimicrobial treatments. In addition, they appear to prevent recurrent infections in certain subgroups of children, such as in infection-prone children with allergic diseases. Alleviating ARI by probiotics may lead to a marginal reduction in the occurrence of AOM in healthy children but not in infection-prone children with disturbed nasopharyngeal microbiota. On the basis of these results it could be supposed that Lactobacillus GG or a specific combination containing LGG are effective against viral but not against bacterial otitis, and the mechanism is probably mediated through the stimulation of the immune system. A specific probiotic combination does not reduce respiratory infections in frail elderly subjects. Acute diarrhoea, either in children or in the elderly, is not prevented by the continuous, long-term consumption of probiotics, but the consumption of a specific probiotic combination in a food matrix is beneficial to the oral health of the elderly, through the reduction of the carriage of Candida.
  • Ilveskero, Sorella (Helsingin yliopisto, 2005)
  • Uittamo, Johanna (Helsingin yliopisto, 2012)
    Oral cancer is the seventh most common cancer worldwide and its incidence is increasing. The most important risk factors for oral cancer are chronic alcohol consumption and tobacco smoking, up to 80 % of oral carcinomas are estimated to be caused by alcohol and tobacco. They both trigger an increased level of salivary acetaldehyde, during and after consumption, which is believed to lead to carcinogenesis. Acetaldehyde has multiple mutagenic features and it has recently been classified as a Group 1 carcinogen for humans by the International Agency for Research on Cancer. Acetaldehyde is metabolized from ethanol by microbes of oral microbiota. Some oral microbes possess alcohol dehydrogenase enzyme (ADH) activity, which is the main enzyme in acetaldehyde production. Many microbes are also capable of acetaldehyde production via alcohol fermentation from glucose. However, metabolism of ethanol into acetaldehyde leads to production of high levels of this carcinogen. Acetaldehyde is found in saliva during and after alcohol consumption. In fact, rather low ethanol concentrations (2-20mM) derived from blood to saliva are enough for microbial acetaldehyde production. The high acetaldehyde levels in saliva after alcohol challenge are explained by the lack of oral microbiota and mucosa to detoxify acetaldehyde by metabolizing it into acetate and acetyl coenzymeA. The aim of this thesis project was to specify the role of oral microbes in the in vitro production of acetaldehyde in the presence of ethanol. In addition, it was sought to establish whether microbial metabolism could also produce acetaldehyde from glucose. Furthermore, the potential of xylitol to inhibit ethanol metabolism and acetaldehyde production was explored. Isolates of oral microbes were used in the first three studies. Acetaldehyde production was analyzed after ethanol, glucose and fructose incubation with gas chromatography measurement. In studies I and III, the ADH enzyme activity of some microbes was measured by fluorescence. The effect of xylitol was analyzed by incubating microbes with ethanol and xylitol. The fourth study was made ex vivo and microbial samples obtained from different patient groups were analyzed. This work has demonstrated that isolates of oral microbiota are able to produce acetaldehyde in the presence of clinically relevant ethanol and glucose concentrations. Significant differences were found between microbial species and isolates from different patient groups. In particular, the ability of candidal isolates from APECED patients to produce significantly more acetaldehyde in glucose incubation compared to healthy and cancer patient isolates is an interesting observation. Moreover, xylitol was found to reduce their acetaldehyde production significantly. Significant ADH enzyme activity was found in the analyzed high acetaldehyde producing streptococci and candida isolates. In addition, xylitol was found to reduce the ADH enzyme activity of C. albicans. Some results from the ex vivo study were controversial, since acetaldehyde production did not correlate as expected with the amount of microbes in the samples. Nevertheless, the samples isolated from patients did produce significant amounts of acetaldehyde with a clinically relevant ethanol concentration.
  • Siironen, Päivi (Helsingin yliopisto, 2005)
  • Koskensalo, Selja (Helsingin yliopisto, 2013)
    Background and aims: The most important prognostic factor in colorectal cancer (CRC) is tumour stage. Prognosis of local tumours is good, but in tumours with lymph node or distant metastasis, the prognosis is worse. Patients with stage III (Dukes C) tumours usually receive adjuvant chemotherapy. Patients with stage IV (Dukes D) tumours cannot be treated curatively by surgery alone and usually receive chemotherapy. In stage II (Dukes B) disease, adjuvant chemotherapy is recommended for patients at risk for recurrence, such as with tumours with vascular or perineural invasion, or in cases with emergency surgery or insufficient lymph-node harvest. In order to identify better those patients requires additional prognostic factors like biomarkers. Material and methods: Clinical data came from 643 consecutive patients who underwent surgery for colorectal cancer at the Department of Surgery, Meilahti Hospital, Helsinki University Central Hospital, between 1982 and 1998. Clinical data and archival tissue specimens were available from 623 cases. For MMP-9, a validation series of 213 patients treated between 1998 and 2001 was included. Survival data came from the Population Register Centre of Finland and Statistics Finland. Tissue microarray (TMA) blocks were prepared from re-evaluated histological archive blocks. TMA slides were stained with MMP-2, MMP-7, MMP-8, MMP-9, TATI, trypsinogen-1, trypsinogen-2, p53, Ki-67, and EGFR antibodies. Correlation of immunoexpression of markers with clinicopathological variables was assessed. Survival analysis was performed by the Kaplan-Meier method, and multivariate Cox proportional hazards model. Results: Study I showed strong MMP-7 to be an independent prognostic marker for 5-year survival, but later the difference faded. In Study II, no association was observable between p53 or Ki-67 expression and survival. In Study III, TATI immunoexpression was an independent prognostic marker for improved survival, particularly in subgroups of trypsinogen-1- and trypsinogen-2-positive patients, although trypsinogen-1 and trypsinogen-2 were not prognostic factors. In Study IV, MMP-9 expression was an independent prognostic marker of favourable survival in Dukes B patients, but the validation series did not confirm these results. MMP-2 and MMP-8 immunoexpression lacked any correlation with prognosis. In Study V, EGFR+TATI+ patients had significantly better prognosis than did those with EGFR+TATI-, EGFR-TATI+, or EGFR-TATI-. Conclusion: MMP-7, MMP-9, TATI, and the TATI-EGFR combination can all serve as prognostic biomarkers in CRC.
  • Kanerva, Jukka (Helsingin yliopisto, 2002)
  • Koljonen, Virve (Helsingin yliopisto, 2004)
  • Ilmonen, Suvi (Helsingin yliopisto, 2005)
  • Taskinen, Minna (Helsingin yliopisto, 2011)
    Follicular lymphoma (FL) is the second most common non-Hodgkin lymphoma. It is an indolent and clinically heterogeneous disease, which is generally considered incurable. Currently, immunochemotherapy has significantly improved the outcome of FL patients. This is based on the combination of rituximab, a monoclonal anti-CD20 antibody, with chemotherapy, and is used at present as a standard first-line therapy in FL. Thus far, however, patients have been selected for treatment based on clinical risk factors and indices that were developed before the rituximab era. Therefore, there is a growing need to understand the molecular mechanisms underlying the disease, which would not only provide information to predict survival in the rituximab era, but also enable the design of more targeted therapeutic strategies. In this study, our aim was to identify genes predicting the outcome in FL patients treated with immunochemotherapy. Thus, we performed a cDNA microarray with 24 FL patients. When gene expression differences from diagnostic tumour samples were related to the clinical outcome, we identified novel genes with a prognostic impact on survival. The expression of selected genes was further characterized with quantitative PCR and immunohistochemistry (IHC). Interestingly, the prognostic influence of these genes was often associated with their expression in non-malignant cells instead of tumour cells. Based on the observed gene expression patterns, we analyzed the abundance and prognostic value of non-malignant immune cells in 95-98 FL patients treated with immunochemotherapy. We observed that a high content of tumour-associated macrophages was a marker of a favourable prognosis. In contrast, the accumulation of mast cells correlated with a poor outcome and was further associated with tumour vascularity. Increased microvessel density also correlated with an inferior outcome. In addition, we used the same microarray data with a systems biology approach to identify signalling pathways or groups of genes capable of separating patients with favourable or adverse outcomes. Among the transcripts, there were many genes associated with signal transducers and activators of the transcription (STAT5a) pathway. When IHC was used as validation, STAT5a expression was mostly observed in T-cells and follicular dendritic cells, and expression was found to predict a favourable outcome. In cell cultures, rituximab was observed to induce the expression of STAT5a-associated interleukins in human lymphoma cell lines, which might provide a possible link for the cross-talk between rituximab-induced FL cells and their microenvironment. In conclusion, we have demonstrated that the microenvironment has a prognostic role in FL patients treated with immunochemotherapy. The results also address the importance of re-evaluating the prognostic markers in the rituximab era of lymphoma therapies.
  • Mäkitie, Teemu (Helsingin yliopisto, 2001)
  • Koskinen, Walter (Helsingin yliopisto, 2006)
    Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. Well-known risk factors include tobacco smoking and alcohol consumption. Overall survival has improved, but is still low especially in developing countries. One reason for this is the often advanced stage of the disease at the time of diagnosis, but also lack of reliable prognostic tools to enable individualized patient treatment to improve outcome. To date, the TNM classification still serves as the best disease evaluation criterion, although it does not take into account the molecular basis of the tumor. The need for surrogate molecular markers for more accurate disease prediction has increased research interests in this field. We investigated the prevalence, physical status, and viral load of human papillomavirus (HPV) in HNSCC to determine the impact of HPV on head and neck carcinogenesis. The prevalence and genotyping of HPV were assessed with an SPF10 PCR microtiter plate-based hybridization assay (DEIA), followed by a line probe-based genotyping assay. More than half of the patients had HPV DNA in their tumor specimens. Oncogenic HPV-16 was the most common type, and coinfections with other oncogenic and benign associated types also existed. HPV-16 viral load was unevenly distributed among different tumor sites; the tonsils harbored significantly greater amounts of virus than other sites. Episomal location of HPV-16 was associated with large tumors, and both integrated and mixed forms of viral DNA were detected. In this series, we could not show that the presence of HPV DNA correlated with survival. In addition, we investigated the prevalence and genotype of HPV in laryngeal carcinoma patients in a prospective Nordic multicenter study based on fresh-frozen laryngeal tumor samples to determine whether the tumors were HPV-associated. These patients were also examined and interviewed at diagnosis for known risk factors, such as tobacco smoking and alcohol consumption, and for several other habituations to elucidate their effects on patient survival. HPV analysis was performed with the same protocols as in the first study. Only 4% of the specimens harbored HPV DNA. Heavy drinking was associated with poor survival. Heavy drinking patients were also younger than nonheavy drinkers and had a more advanced stage of disease at diagnosis. Heavy drinkers had worse oral hygiene than nonheavy drinkers; however, poor oral hygiene did not have prognostic significance. History of chronic laryngitis, gastroesophageal reflux disease, and orogenital sex contacts were rare in this series. To clarify why vocal cord carcinomas seldom metastasize, we determined tumor lymph vessel (LVD) and blood vessel (BVD) densities in HNSCC patients. We used a novel lymphatic vessel endothelial marker (LYVE-1 antibody) to locate the lymphatic vessels in HNSCC samples and CD31 to detect the blood microvessels. We found carcinomas of the vocal cords to harbor less lymphatic and blood microvessels than carcinomas arising from sites other than vocal cords. The lymphatic and blood microvessel densities did not correlate with tumor size. High BVD was strongly correlated with high LVD. Neither BVD nor LVD showed any association with survival in our series. The immune system plays an important role in tumorigenesis, as neoplastic cells have to escape the cytotoxic lymphocytes in order to survive. Several candidate HLA class II alleles have been reported to be prognostic in cervical carcinomas, an epithelial malignancy resembling HNSCC. These alleles may have an impact on head and neck carcinomas as well. We determined HLA-DRB1* and -DQB1* alleles in HNSCC patients. Healthy organ donors served as controls. The Inno-LiPA reverse dot-blot kit was used to identify alleles in patient samples. No single haplotype was found to be predictive of either the risk for head and neck cancer, or the clinical course of the disease. However, alleles observed to be prognostic in cervical carcinomas showed a similar tendency in our series. DRB1*03 was associated with node-negative disease at diagnosis. DRB1*08 and DRB1*13 were associated with early-stage disease; DRB1*04 had a lower risk for tumor relapse; and DQB1*03 and DQB1*0502 were more frequent in controls than in patients. However, these associations reached only borderline significance in our HNSCC patients.
  • Jernman, Juha (Helsingin yliopisto, 2015)
    Neuroendocrine tumors of the rectum were regarded as benign, when Oberndorfer originally described the entity in 1907. Later, he acknowledged that some neuroendocrine tumors (or carcinoids, the term at that time) behave in a more aggressive manner, and a few of them even had the potential to metastasize with poor outcome. In the novel World Health Organization (WHO) classification launched in 2010, all neuroendocrine tumors of the gastrointestinal (GI) tract are malignant. In this classification, tumors of every part of the GI tract are graded uniformly according to proliferation index and mitotic frequency, whereas the TNM-classification (tumor, node, metastasis) is specific for each site. Around 10% of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) occur in the rectum. The tumor series comprised 73 rectal NETs, with the main objective being to study the prognostic value of the WHO 2010 classification in rectal NETs: additionally, as the WHO classification has been used for a rather short time, tumor markers were tested to find a good, reliable prognostic tool. The WHO 2010 had excellent prognostic significance; none of the G1-NETs (grade 1) metastasized, whereas G2-NETs were often disseminated, some of them at initial presentation. Metastatic NETs have a poor prognosis. Cell-cycle antigen cyclin A also correlated with prognosis, and G2-NETs with high cyclin A expression were all metastatic. Transcription factor prospero homeobox 1 (PROX1) was immunohistochemically positive in a significant proportion of rectal NETs, and showed a correlation with metastatic potential and survival. It was also possible to conclude that the novel stem cell-associated factor HES77 (human embryonic stem cell factor 77) correlated well with rectal NETs metastatic potential and prognosis. These results support the validity of the WHO 2010 classification in rectal NETs. In view of this study, for patients with a rectal G1-NET, one follow-up endoscopy to exclude local recurrence might suffice. Intensive follow-up does not seem indicated, as metastatic potential is very low. As to G2-NETs, a thorough work-up is recommended, since most of these tumors disseminate eventually, some after several years, and a standard 5-year follow-up may not suffice. PROX1-positivity suggests that colorectal adenocarcinoma and rectal NET may, to some extent, share the same pathway in oncogenesis, which could lead to future therapeutic applications.
  • Raj, Rahul (Helsingin yliopisto, 2014)
    Background: Prognostic models are important tools for heterogeneity adjustment in traumatic brain injury (TBI). Prognoses after TBI have been particularly challenging to predict, with limited availability of robust prognostic models. TBI patients are by definition trauma patients, and often treated in the intensive care unit (ICU). Several prognostic models for ICU and trauma patients have been developed, although their applicability in patients with TBI is uncertain. Recently, however, some new prognostic models specifically designed for patients with TBI were introduced. Still, the optimal type of prognostic model in TBI remains unknown. Aim: To investigate the applicability of different types of prognostic models in patients with TBI and to develop novel models with enhanced performance to previous models, focusing on long- term outcome prediction. Methods: Four patient databases of patients with TBI treated in the ICU were used to validate three TBI specific models, two computerized tomography (CT) scoring systems, one trauma scoring system, and three intensive care scoring systems. Models were validated by assessing their discrimination using area under the curve (AUC), calibration, and explanatory variation. Logistic regression was used for model customization and development. Models were internally validated using a resample bootstrap technique or a split-sample technique. Primary outcome was six-month mortality and unfavorable neurological outcome by the Glasgow Outcome Scale. 30-day in-hospital mortality was used for the trauma scoring system. Results: Study populations ranged from 342 to 9,915 patients. The TBI models showed the best performance with AUCs between 0.80 and 0.85, followed by the intensive care scoring systems and the CT scores with AUCs between 0.68 to 0.80 and 0.63 to 0.70, respectively. Most models showed poor calibration, although good calibration was achieved following customization. The trauma scoring system exhibited modest to good discrimination (AUC 0.76-0.89) for short-term mortality prediction, but poor calibration. Several new prognostic models, with statistically significant superior performance to previous models were created, among them a combined TBI-ICU model ( IMPACT-APACHE ) and a novel CT scoring system ( The Helsinki CT score ). Using a TBI specific model, based on admission characteristics, up to 40 % of the patient s final long-term outcome could be predicted. Conclusion: The TBI models showed superior predictive performance to the intensive care and trauma scoring systems, showing that TBI patients are a highly specific population in the trauma and ICU setting. Thus, the use of a TBI specific model is advocated in the setting of TBI. The newly proposed models were found to be significant improvements over previous models, but require external validation to show generalizability.
  • Nyman, Heidi (Helsingin yliopisto, 2010)
    Diffuse large B-cell lymphoma (DLBCL) is the most common of the non-Hodgkin lymphomas. As DLBCL is characterized by heterogeneous clinical and biological features, its prognosis varies. To date, the International Prognostic Index has been the strongest predictor of outcome for DLBCL patients. However, no biological characters of the disease are taken into account. Gene expression profiling studies have identified two major cell-of-origin phenotypes in DLBCL with different prognoses, the favourable germinal centre B-cell-like (GCB) and the unfavourable activated B-cell-like (ABC) phenotypes. However, results of the prognostic impact of the immunohistochemically defined GCB and non-GCB distinction are controversial. Furthermore, since the addition of the CD20 antibody rituximab to chemotherapy has been established as the standard treatment of DLBCL, all molecular markers need to be evaluated in the post-rituximab era. In this study, we aimed to evaluate the predictive value of immunohistochemically defined cell-of-origin classification in DLBCL patients. The GCB and non-GCB phenotypes were defined according to the Hans algorithm (CD10, BCL6 and MUM1/IRF4) among 90 immunochemotherapy- and 104 chemotherapy-treated DLBCL patients. In the chemotherapy group, we observed a significant difference in survival between GCB and non-GCB patients, with a good and a poor prognosis, respectively. However, in the rituximab group, no prognostic value of the GCB phenotype was observed. Likewise, among 29 high-risk de novo DLBCL patients receiving high-dose chemotherapy and autologous stem cell transplantation, the survival of non-GCB patients was improved, but no difference in outcome was seen between GCB and non-GCB subgroups. Since the results suggested that the Hans algorithm was not applicable in immunochemotherapy-treated DLBCL patients, we aimed to further focus on algorithms based on ABC markers. We examined the modified activated B-cell-like algorithm based (MUM1/IRF4 and FOXP1), as well as a previously reported Muris algorithm (BCL2, CD10 and MUM1/IRF4) among 88 DLBCL patients uniformly treated with immunochemotherapy. Both algorithms distinguished the unfavourable ABC-like subgroup with a significantly inferior failure-free survival relative to the GCB-like DLBCL patients. Similarly, the results of the individual predictive molecular markers transcription factor FOXP1 and anti-apoptotic protein BCL2 have been inconsistent and should be assessed in immunochemotherapy-treated DLBCL patients. The markers were evaluated in a cohort of 117 patients treated with rituximab and chemotherapy. FOXP1 expression could not distinguish between patients, with favourable and those with poor outcomes. In contrast, BCL2-negative DLBCL patients had significantly superior survival relative to BCL2-positive patients. Our results indicate that the immunohistochemically defined cell-of-origin classification in DLBCL has a prognostic impact in the immunochemotherapy era, when the identifying algorithms are based on ABC-associated markers. We also propose that BCL2 negativity is predictive of a favourable outcome. Further investigational efforts are, however, warranted to identify the molecular features of DLBCL that could enable individualized cancer therapy in routine patient care.
  • Mrena, Johanna (Helsingin yliopisto, 2011)
    Background and aims: Low stage and curative surgery are established factors for improved survival in gastric cancer. However, not all low-stage patients have a good prognosis. Cyclooxygenase-2 (COX-2) is known to associate with reduced survival in several cancers, and has been shown to play an important role in gastric carcinogenesis. Since new and better prognostic markers are needed for gastric cancer, we studied the prognostic significance of COX-2 and of markers that associate with COX-2 expression. We also studied markers reflecting proliferation and apoptosis, and evaluated their association with COX-2. Our purpose was to construct an accurate prognostic model by combining tissue markers and clinicopathogical factors. Materials and methods: Of 342 consecutive patients who underwent surgery for gastric cancer at Meilahti Hospital, Helsinki University Central Hospital, 337 were included in this study. Low stages I to II were represented by 141 (42%) patients, and high stages III to IV by 196 (58%). Curative surgery was performed on 176 (52%) patients. Survival data were obtained from the national registers. Slides from archive tissue blocks were prepared for immunohistochemistry by use of COX-2, human antigen R (HuR), cyclin A, matrix metalloproteinases 2 and 9 (MMP-2, MMP-9), and Ki-67 antibodies. Immunostainings were scored by microscopy, and scores were entered into a database. Associations of tumor markers with clinicopathological factors were calculated, as well as associations with p53, p21, and results of flow cytometry from earlier studies. Survival analysis was performed by the Kaplan-Meier method, and Cox multivariate models were reconstructed. Cell culture experiments were performed to explore the effect of small interfering (si)RNA of HuR on COX-2 expression in a TMK-1 gastric cancer cell line. Results: Overall 5-year survival was 35.1%. Study I showed that COX-2 was an independent prognostic factor, and that the prognostic impact of COX-2 was more pronounced in low-stage patients. Cytoplasmic HuR expression also associated with reduced survival in gastric cancer patients in a non-independent manner. Cell culture experiments showed that HuR can regulate COX-2 expression in TMK-1 cells in vitro, with an association also between COX-2 and HuR tissue expression in a clinical material. In Study II, cyclin A was an independent prognostic factor and was associated with HuR expression in the gastric cancer material. The results of Study III showed that epithelial MMP-2 associated with survival in univariate, but not in multivariate analysis. However, MMP-9 showed no prognostic value. MMP-2 expression was associated with COX-2 expression. In Study IV, the prognostic power of COX-2 was compared with that of all tested markers associated with survival in Studies I to III, as well as with p21, p53, and flow cytometry results. COX-2 and p53 were independent prognostic factors, and COX-2 expression was associated with that of p53 and Ki-67 and also with aneuploidy. Conclusions: COX-2 is an independent prognostic factor in gastric cancer, and its prognostic power emerges especially in low stage cancer. COX-2 is regulated by HuR, and is associated with factors reflecting invasion, proliferation, and apoptosis. In an extended multivariate model, COX-2 retained its position as an independent prognosticator. COX-2 can be considered a promising new prognostic marker in gastric cancer.
  • Juuti, Anne (Helsingin yliopisto, 2006)
    Background. Pancreatic cancer is one of the major causes of cancer death in the industrialised world. The overall survival of patients with ductal pancreatic adenocarcinoma is poor: 5-year survival is only 0.2 to 4%. Tumour stage and histological grade are used as prognostic markers in pancreatic cancer. However, there are differences in survival within stages and histological grades. New, additional and more accurate prognostic tools are needed. Aims. The purpose of this study was to investigate whether the tissue expression of potential and promising tumour markers p27, tenascin C, syndecan-1, COX-2 and MMP-2 are associated with clinicopathological parameters in pancreatic cancer. The expression of p27, tenascin C and syndecan-1 was also evaluated in acute and chronic pancreatitis. The main purpose in the study was to find new prognostic markers for pancreatic adenocarcinoma. Patients. The study included 147 patients with histologically verified pancreatic adenocarcinoma treated at Helsinki University Central Hospital from 1974 to1998. Methods. The expression of tumour marker antigens was demonstrated by immunohistochemistry using monoclonal antibodies against p27, syndecan-1, tenascin C, COX-2 and MMP-2. The results were compared with clinicopathological variables, i.e. age, sex, TNM stage and histological grade. Survival analyses were performed with univariate Kaplan-Meier life-tables and the log-rank test, while multivariate analyses were performed using Cox regression. Results. Pancreatic adenocarcinomas expressed p27, syndecan-1, tenascin C, COX-2 and MMP-2 in 30, 94, 92, 36 and 50% of the samples, respectively. Loss of p27 expression was associated with poor prognosis in stage I and II pancreatic cancer. Stromal syndecan-1 expression was an independent prognostic marker in pancreatic cancer, whereas epithelial syndecan-1 expression predicted better prognosis only in stage I and II disease. Tenascin C expression did not correlate with survival but was associated with differentiation. COX-2 expression was associated with poor outcome and was an independent prognostic factor. Epithelial MMP-2 correlated with poor prognosis in pancreatic cancer. Conclusion: p27 and epithelial syndecan-1 are prognostic markers in early (stage I and II) pancreatic cancer. Stromal syndecan-1, COX-2 and epithelial MMP-2 are prognostic factors in ductal pancreatic adenocarcinoma.