Browsing by Subject "COPY NUMBER"

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  • Wolf, Maija; Korja, Miikka; Karhu, Ritva; Edgren, Henrik; Kilpinen, Sami; Ojala, Kalle; Mousses, Spyro; Kallioniemi, Anne; Haapasalo, Hannu (2010)
    Neuroblastoma has successfully served as a model system for the identification of neuroectoderm-derived oncogenes. However, in spite of various efforts, only a few clinically useful prognostic markers have been found. Here, we present a framework, which integrates DNA, RNA and tissue data to identify and prioritize genetic events that represent clinically relevant new therapeutic targets and prognostic biomarkers for neuroblastoma.
  • Chen, Ping; Lepikhova, Tatiana; Hu, Yizhou; Monni, Outi; Hautaniemi, Sampsa (2011)
  • Mäki-Nevala, Satu; Valo, Satu; Ristimaki, Ari; Sarhadi, Virinder; Knuutila, Sakari; Nyström, Minna; Renkonen-Sinisalo, Laura; Lepistö, Anna; Mecklin, Jukka-Pekka; Peltomäki, Päivi (2019)
    Background: DNA mismatch repair (MMR) defects are a major factor in colorectal tumorigenesis in Lynch syndrome (LS) and 15% of sporadic cases. Some adenomas from carriers of inherited MMR gene mutations have intact MMR protein expression implying other mechanisms accelerating tumorigenesis. We determined roles of DNA methylation changes and somatic mutations in cancer-associated genes as tumorigenic events in LS-associated colorectal adenomas with intact MMR. Methods: We investigated 122 archival colorectal specimens of normal mucosae, adenomas and carcinomas from 57 LS patients. MMR-deficient (MMR-D, n 49) and MMR-proficient (MMR-P, n 18) adenomas were of particular interest and were interrogated by methylation-specific multiplex ligation-dependent probe amplification and Ion Torrent sequencing. Findings: Promoter methylation of CpG island methylator phenotype (CIMP)-associated marker genes and selected colorectal cancer (CRC)-associated tumor suppressor genes (TSGs) increased and LINE-1 methylation decreased from normal mucosa to MMR-P adenomas to MMR-D adenomas. Methylation differences were statistically significant when either adenoma group was compared with normal mucosa, but not between MMR-P and MMR-D adenomas. Significantly increased methylation was found in multiple CIMP marker genes (1612, NEUROGI,CRABP1, and CDKN2A) and TSGs (SERPI and SFRP2) in MMR-P adenomas already. Furthermore, certain CRC-associated somatic mutations, such as KRAS, were prevalent in MMR-P adenomas. Interpretation: We conclude that DNA methylation changes and somatic mutations of cancer-associated genes might serve as an alternative pathway accelerating LS-associated tumorigenesis in the presence of proficient MMR. Fund: Jane and Aatos Erkko Foundation, Academy of Finland, Cancer Foundation Finland, Sigrid juselius Foundation, and HiL1FE. (C) 2019 Published by Elsevier B.V.
  • Nordlund, Jessica; Backlin, Christofer L.; Zachariadis, Vasilios; Cavelier, Lucia; Dahlberg, Johan; Ofverholm, Ingegerd; Barbany, Gisela; Nordgren, Ann; Overnas, Elin; Abrahamsson, Jonas; Flaegstad, Trond; Heyman, Mats M.; Jonsson, Olafur G.; Kanerva, Jukka; Larsson, Rolf; Palle, Josefine; Schmiegelow, Kjeld; Gustafsson, Mats G.; Lonnerholm, Gudmar; Forestier, Erik; Syvanen, Ann-Christine (2015)
  • Jernström, Sandra; Hongisto, Vesa; Leivonen, Suvi-Katri; Due, Eldri Undlien; Tadele, Dagim Shiferaw; Edgren, Henrik; Kallioniemi, Olli; Perälä, Merja; Mlandsmo, Gunhild Mari; Sahlberg, Kristine Kleivi (2017)
    Background: Approximately 15%-20% of all diagnosed breast cancers are characterized by amplified and overexpressed HER2 (= ErbB2). These breast cancers are aggressive and have a poor prognosis. Although improvements in treatment have been achieved after the introduction of trastuzumab and lapatinib, many patients do not benefit from these drugs. Therefore, in-depth understanding of the mechanisms behind the treatment responses is essential to find alternative therapeutic strategies. Materials and methods: Thirteen HER2 positive breast cancer cell lines were screened with 22 commercially available compounds, mainly targeting proteins in the ErbB2-signaling pathway, and molecular mechanisms related to treatment sensitivity were sought. Cell viability was measured, and treatment responses between the cell lines were compared. To search for response predictors and genomic and transcriptomic profiling, PIK3CA mutations and PTEN status were explored and molecular features associated with drug sensitivity sought. Results: The cell lines were divided into three groups according to the growth-retarding effect induced by trastuzumab and lapatinib. Interestingly, two cell lines insensitive to trastuzumab (KPL4 and SUM190PT) showed sensitivity to an Akt1/2 kinase inhibitor. These cell lines had mutation in PIK3CA and loss of PTEN, suggesting an activated and druggable Akt-signaling pathway. Expression levels of five genes (CDC42, MAPK8, PLCG1, PTK6, and PAK6) were suggested as predictors for the Akt1/2 kinase-inhibitor response. Conclusion: Targeting the Akt-signaling pathway shows promise in cell lines that do not respond to trastuzumab. In addition, our results indicate that several molecular features determine the growth-retarding effects induced by the drugs, suggesting that parameters other than HER2 amplification/expression should be included as markers for therapy decisions.
  • Porkka, Noora; Lahtinen, Laura; Ahtiainen, Maarit; Böhm, Jan P.; Kuopio, Teijo; Eldfors, Samuli; Mecklin, Jukka-Pekka; Seppälä, Toni T.; Peltomäki, Päivi (2019)
    Colorectal carcinomas that are mismatch repair (MMR)-deficient in the absence of MLH1 promoter methylation or germline mutations represent Lynch-like syndrome (LLS). Double somatic events inactivating MMR genes are involved in the etiology of LLS tumors. Our purpose was to define the clinical and broader molecular hallmarks of LLS tumors and the population incidence of LLS, which remain poorly characterized. We investigated 762 consecutive colorectal carcinomas operated in Central Finland in 2000-2010. LLS cases were identified by a stepwise protocol based on MMR protein expression, MLH1 methylation and MMR gene mutation status. LLS tumors were profiled for CpG Island Methylator Phenotype (CIMP) and somatic mutations in 578 cancer-relevant genes. Among 107 MMR-deficient tumors, 81 (76%) were attributable to MLH1 promoter methylation and 9 (8%) to germline mutations (Lynch syndrome, LS), leaving 14 LLS cases (13%) (3 remained unclassified). LLS carcinomas were diagnosed at a mean age of 65 years (vs. 44 years in LS, p <0.001), had a proximal to distal ratio of 1:1, and all were BRAF V600E-negative. Two somatic events in MMR genes were identifiable in 11 tumors (79%). As novel findings, the tumors contained an average of 31 nonsynonymous somatic mutations/Mb and 13/14 were CIMP-positive. In conclusion, we establish the epidemiological, clinical and molecular characteristics of LLS in a population-based study design. Significantly more frequent CIMP-positivity and lower rates of somatic mutations make a distinction to LS. The absence of BRAF V600E mutation separates LLS colorectal carcinomas from MLH1-methylated colorectal carcinomas with CIMP-positive phenotype.
  • Kjällquist, Una; Erlandsson, Rikard; Tobin, Nicholas P.; Alkodsi, Amjad; Ullah, Ikram; Stalhammar, Gustav; Karlsson, Eva; Hatschek, Thomas; Hartman, Johan; Linnarsson, Sten; Bergh, Jonas (2018)
    Background: Tumor heterogeneity in breast cancer tumors is today widely recognized. Most of the available knowledge in genetic variation however, relates to the primary tumor while metastatic lesions are much less studied. Many studies have revealed marked alterations of standard prognostic and predictive factors during tumor progression. Characterization of paired primary- and metastatic tissues should therefore be fundamental in order to understand mechanisms of tumor progression, clonal relationship to tumor evolution as well as the therapeutic aspects of systemic disease. Methods: We performed full exome sequencing of primary breast cancers and their metastases in a cohort of ten patients and further confirmed our findings in an additional cohort of 20 patients with paired primary and metastatic tumors. Furthermore, we used gene expression from the metastatic lesions and a primary breast cancer data set to study the gene expression of the AKAP gene family. Results: We report that somatic mutations in A-kinase anchoring proteins are enriched in metastatic lesions. The frequency of mutation in the AKAP gene family was 10% in the primary tumors and 40% in metastatic lesions. Several copy number variations, including deletions in regions containing AKAP genes were detected and showed consistent patterns in both investigated cohorts. In a second cohort containing 20 patients with paired primary and metastatic lesions, AKAP mutations showed an increasing variant allele frequency after multiple relapses. Furthermore, gene expression profiles from the metastatic lesions (n = 120) revealed differential expression patterns of AKAPs relative to the tumor PAM50 intrinsic subtype, which were most apparent in the basal-like subtype. This pattern was confirmed in primary tumors from TCGA (n = 522) and in a third independent cohort (n = 182). Conclusion: Several studies from primary cancers have reported individual AKAP genes to be associated with cancer risk and metastatic relapses as well as direct involvement in cellular invasion and migration processes. Our findings reveal an enrichment of mutations in AKAP genes in metastatic breast cancers and suggest the involvement of AKAPs in the metastatic process. In addition, we report an AKAP gene expression pattern that consistently follows the tumor intrinsic subtype, further suggesting AKAP family members as relevant players in breast cancer biology.
  • Maliniemi, Pilvi; Vincendeau, Michelle; Mayer, Jens; Frank, Oliver; Hahtola, Sonja; Karenko, Leena; Carlsson, Emilia; Mallet, Francois; Seifarth, Wolfgang; Leib-Moesch, Christine; Ranki, Annamari (2013)
  • Woodcock, D. J.; Riabchenko, E.; Taavitsainen, S.; Kankainen, M.; Gundem, G.; Brewer, D. S.; Ellonen, P.; Lepistö, M.; Golubeva, Y. A.; Warner, A. C.; Tolonen, T.; Jasu, J.; Isaacs, W. B.; Emmert-Buck, M. R.; Nykter, M.; Visakorpi, T.; Bova, G. S.; Wedge, D. C. (2020)
    The evolutionary progression from primary to metastatic prostate cancer is largely uncharted, and the implications for liquid biopsy are unexplored. We infer detailed reconstructions of tumor phylogenies in ten prostate cancer patients with fatal disease, and investigate them in conjunction with histopathology and tumor DNA extracted from blood and cerebrospinal fluid. Substantial evolution occurs within the prostate, resulting in branching into multiple spatially intermixed lineages. One dominant lineage emerges that initiates and drives systemic metastasis, where polyclonal seeding between sites is common. Routes to metastasis differ between patients, and likely genetic drivers of metastasis distinguish the metastatic lineage from the lineage that remains confined to the prostate within each patient. Body fluids capture features of the dominant lineage, and subclonal expansions that occur in the metastatic phase are non-uniformly represented. Cerebrospinal fluid analysis reveals lineages not detected in blood-borne DNA, suggesting possible clinical utility. The evolutionary progression from primary to metastatic prostate cancer is largely uncharted, and the implications for liquid biopsy are unexplored. Here, the authors use deep genomic sequencing and histopathological information to trace tumor evolution both within the prostate and during metastasis in ten men.
  • Tanaka, Atsushi; Ide, Tomomi; Fujino, Takeo; Onitsuka, Ken; Ikeda, Masataka; Takehara, Takako; Hata, Yuko; Ylikallio, Emil; Tyynismaa, Henna; Suomalainen, Anu; Sunagawa, Kenji (2013)
  • Brunelli, Matteo; Bria, Emilio; Nottegar, Alessia; Cingarlini, Sara; Simionato, Francesca; Calio, Anna; Eccher, Albino; Parolini, Claudia; Iannucci, Antonio; Gilioli, Eliana; Pedron, Serena; Massari, Francesco; Tortora, Giampaolo; Borze, Florentina Ioana; Knuutila, Sakari; Gobbo, Stefano; Santo, Antonio; Tondulli, Luca; Calabro, Francesco; Martignoni, Guido; Chilosi, Marco (2012)