In order to uncover miRNA changes in endometriosis pathogenesis, both endometriotic lesions and endometrial biopsies, as well as stromal and epithelial cells isolated from these tissues have been investigated and a large number of dysregulated miRNAs have been reported. However, the concordance between the result of different studies has remained small. One potential explanation for limited overlap between the proposed disease-related miRNAs could be the heterogeneity in tissue composition, as some studies have compared highly heterogeneous whole-lesion biopsies with endometrial tissue, some have compared the endometrium from patients and controls, and some have used pure cell fractions isolated from lesions and endometrium. This review focuses on the results of published miRNA studies in endometriosis to reveal the potential impact of tissue heterogeneity on the discovery of disease-specific miRNA alterations in endometriosis. Additionally, functional studies that explore the roles of endometriosis-involved miRNAs are discussed.

Abstract Background Breast cancer is a heterogeneous disease at the clinical and molecular level. In this study we integrate classifications extracted from five different molecular levels in order to identify integrated subtypes. Methods Tumor tissue from 425 patients with primary breast cancer from the Oslo2 study was cut and blended, and divided into fractions for DNA, RNA and protein isolation and metabolomics, allowing the acquisition of representative and comparable molecular data. Patients were stratified into groups based on their tumor characteristics from five different molecular levels, using various clustering methods. Finally, all previously identified and newly determined subgroups were combined in a multilevel classification using a “cluster-of-clusters” approach with consensus clustering. Results Based on DNA copy number data, tumors were categorized into three groups according to the complex arm aberration index. mRNA expression profiles divided tumors into five molecular subgroups according to PAM50 subtyping, and clustering based on microRNA expression revealed four subgroups. Reverse-phase protein array data divided tumors into five subgroups. Hierarchical clustering of tumor metabolic profiles revealed three clusters. Combining DNA copy number and mRNA expression classified tumors into seven clusters based on pathway activity levels, and tumors were classified into ten subtypes using integrative clustering. The final consensus clustering that incorporated all aforementioned subtypes revealed six major groups. Five corresponded well with the mRNA subtypes, while a sixth group resulted from a split of the luminal A subtype; these tumors belonged to distinct microRNA clusters. Gain-of-function studies using MCF-7 cells showed that microRNAs differentially expressed between the luminal A clusters were important for cancer cell survival. These microRNAs were used to validate the split in luminal A tumors in four independent breast cancer cohorts. In two cohorts the microRNAs divided tumors into subgroups with significantly different outcomes, and in another a trend was observed. Conclusions The six integrated subtypes identified confirm the heterogeneity of breast cancer and show that finer subdivisions of subtypes are evident. Increasing knowledge of the heterogeneity of the luminal A subtype may add pivotal information to guide therapeutic choices, evidently bringing us closer to improved treatment for this largest subgroup of breast cancer.

Background: Malignant mesothelioma is a fatal cancer of the mesothelial cells characterized by previous exposure to asbestos, long latency period and shorter survival time thereafter. Lack of highly sensitive and specific biomarkers and no curative treatment at present has made the continuous study of mesothelioma important. One of the biomarker under study are the microRNAs (miRNAs) which are small non-coding RNAs of about 20-22 nucleotides long which regulate post-translational gene expression. MiRNAs control several essential biological pathways including the epithelial-mesenchymal transition (EMT) pathway. Their dysregulation can lead to disruption of these pathways and also to the development of cancer. Identifying and understanding the role played by these miRNAs in malignant mesothelioma will help in their development as an effective diagnostic, prognostic and therapeutic target for this cancer. Aims: The study aims to first identify miRNAs previously linked with malignant mesothelioma, invasion and the EMT pathway based on review of literature. The study then aims to characterize miRNAs expression in established mesothelial cell lines used widely in mesothelioma research. Material & methods: Literature review is conducted using peer reviewed articles and limiting the articles published within the last 5 years. For characterizing the miRNAs, 6 mesothelial cell lines are used of which one is non-tumorigenic and used to represent a healthy control. Small RNA sequencing is done of all 6 cell lines and results analyzed using the Chipster analysis software. Results: A comprehensive list of 100 miRNAs was created which were linked to malignant mesothelioma, invasion, metastasis and EMT pathway. Small RNA sequencing of the cell lines revealed 134 miRNAs which were expressed in at least one of the cell lines. 34 of these miRNAs had higher counts in the healthy control as compared to all the cancer cell lines. In addition, we found 19 miRNAs having low counts in the control cell line but showed downregulation to zero in all the cancer cell lines. 4 miRNAs, namely miR-10a-5p, miR- 21-5p, miR-23b-3p and miR-183-5p, were also found in this study which were not previously linked with malignant mesothelioma. Conclusion: Characterization of the available mesothelial cell lines is the first step in understanding the role played by miRNAs in the development of this cancer. Further studies are needed to confirm the entire list of mesothelioma associated miRNAs found here, especially the 4 miRNAs which were not previously linked to mesothelioma. Validation of the miRNAs through comparison with patient samples with higher number of biological replicates and greater depth of libraries along with miRNA pathway analysis will help the development of miRNAs as a diagnostic and prognostic marker for this cancer.

Proteomic and genomic techniques have reached full maturity and are providing unforeseen details for the comprehensive understanding of disease pathologies at a fraction of previous costs. However, for kidney diseases, many gaps in such information remain to inhibit major advances in the prevention, treatment and diagnostics of these devastating diseases, which have enormous global impact. The discovery of ubiquitous extracellular vesicles (EV) in all bodily fluids is rapidly increasing the fundamental knowledge of disease mechanisms and the ways in which cells communicate with distant locations in processes of cancer spread, immunological regulation, barrier functions and general modulation of cellular activity. In this review, we describe some of the most prominent research streams and findings utilizing urinary extracellular vesicles as highly versatile and dynamic tools with their extraordinary protein and small regulatory RNA species. While being a highly promising approach, the relatively young field of EV research suffers from a lack of adherence to strict standardization and carefully scrutinized methods for obtaining fully reproducible results. With the appropriate guidelines and standardization achieved, urine is foreseen as forming a unique, robust and easy route for determining accurate and personalized disease signatures and as providing highly useful early biomarkers of the disease pathology of the kidney and beyond.