CNV Identification: Prostate Cancer (PCa) vs Benign Prostatic Hyperplasia (BPH) Human DNA Samples

Copy number variations (CNVs) in the human genome have been linked to various carcinomas including prostate cancer (PCa). This study was conducted to identify CNVs in high grade PCa. We performed a pilot genome-wide CNV analysis in 36 subjects (18 high grade PCa and 18 benign prostatic hyperplasia) using array comparative genomic hybridization (aCGH) technique. Array results were validated using PCR-based copy number counting method. A total of 339 CNV regions were found to be unique to PCa subjects in this cohort (P < 0.05). Data segregation and filtering revealed six putative CNV loci associated with susceptibility to PCa. Of these, four were rare (1q21.3, 15q15, 3q27.2 and 7p12.1) and one was a novel copy number gain (12q23.1), harbouring genes such as the ARNT, THBS1, SLC5A8 and DDC which are crucial in the p53 and cancer pathways. Another CNV was a loss at 8p11.21 which contains the SFRP1 gene from the Wnt signalling pathway, known for its interaction with androgen receptors as reported for urological malignancy. Cross comparison analysis with genes already known to be associated with PCa revealed significant CNVs involved in crucial biological processes that elicit cancer pathogenesis via cytokine production, disease progression through endothelial cell proliferation and xenobiotic metabolism. In conclusion, these findings suggest that the CNV regions identified could provide an insight into the development of high grade PCa. 36 samples were analysed for the purpose of CNV identification (discovery cohort) and 46 other samples ( a different subset of samples) were included in the validation cohort. For the discovery cohort, 18 PCa and 18 BPH samples were used as case and control respectively. Controls in this study was used as the reference itself in order to avoid misinterpretation of data due to reference sample of a different genetic makeup i.e. Yoruba Male- provided in the kit.