The beta subunit of human chorionic gonadotropin (hCGβ) is encoded by six genes (CGB) classified as type I and type II. CGB mRNA is produced in large amounts by trophoblastic tissues and in small amounts by several cancerous tissues including prostate cancer and by a few benign tissues, including the prostate. Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) was used to study the expression levels of all CGB mRNAs together (total CGB mRNA) and the two types of CGB mRNA separately in non-cancerous (n = 74) and cancerous prostatic tissue obtained by radical prostatectomy (n = 193). RNA was isolated from formalin-fixed paraffin-embedded (FFPE) samples and mRNA levels of CGB were correlated with disease-specific survival. Total CGB mRNA concentrations were significantly lower (p < .0001) in cancerous than non-cancerous prostatic tissue. Separate analysis of type I CGB and type II CGB mRNA showed that both type I CGB (p < .0001) and type II CGB mRNA (p = .007) are lower in cancerous tissue than in non-cancerous tissue. Low type II CGB mRNA level in cancerous tissue was associated with shorter cancer-specific survival (p = .001) of prostate cancer patients treated by radical prostatectomy.
Keywords: Human; cancer; chorionic gonadotropin beta; expression; prostate.