| Summary: | Cervical cancer is the third most common cancer among women worldwide, and the fourth leading cause of cancer mortality. Despite significant declines in the incidence and mortality rates of cervical cancer in Canada, it remains the 4th most common cancer in women aged 20-29 years. In order to gain novel insights into cervical cancer tumourigenesis and clinical outcome, we investigated and characterized the alterations in microRNA (miRNA) expression in this disease. Firstly, we performed global miRNA expression profiling of cervical cancer cell lines (n=3), and patient specimens (n=79). From this analysis, we identified miR-196b to be significantly down-regulated in cervical cancer, and characterized its role in regulating the HOXB7~VEGF axis. The global miRNA expression data also led to the development of a candidate 9-miRNA signature that was prognostic for disease-free survival in patients with cervical cancer, although we were unable to validate this signature in an independent cohort. This report describes important considerations concerning the development and validation of microRNA signatures for cervical cancer.
Our investigations also led us to a comparison of three methods for measuring miRNA abundance: the TaqMan Low Density Array, the NanoString nCounter assay, and single-well quantitative real-time PCR. Our findings demonstrated limited concordance between the TLDA and NanoString platforms, although each platform correlated well with PCR, which is considered the gold standard for nucleic acid quantification. Furthermore, we examined biases created by amplification protocols for microarray studies. Our analysis demonstrated that performing a correction using the LTR-method (linear transformation of replicates) could help mitigate, but not completely eliminate such biases.
Overall, this report presents insights into the role of miRNAs in cervical cancer, as well as an evaluation of technical considerations concerning miRNA and mRNA expression profiling studies.
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