Cancer stem cell biomarkers SOX2 and Oct4 in cervical cancer patients undergoing chemoradiotherapy.

Abstract

Cancer stem cell biomarkers SRY (sex-determining region Y)-box 2 (SOX2) and octamer-binding transcription factor 4 (Oct4) account for radioresistance in cervical squamous cell cancers (CSCCs). Their clinical implications are limited and contradictory. In this prospective cohort study, we recruited patients with FIGO IB2-IVA CSCC treated with primary chemoradiotherapy on regular follow-up. Tissue biopsy specimens were evaluated for SOX2 and Oct4 expression by immunohistochemistry, quantified by a product of proportion and intensity scores. A total of 59 patients were included. Most had a moderately differentiated (81%), keratinizing (59%) CSCC, and ≥FIGO stage IIB disease (95%). SOX2 expression (high:low 21:38 patients) and Oct4 expression (high:low 4:55 patients) had a significant interrelation (p=0.005, odds ratio (95% CI) - 1.23 (1.004-1.520)). At a median follow-up of 36 months, the 3-year overall survival (OS) was 60% and 53% for low and high SOX2 expression (p=0.856), and 54% and 100% for low and high Oct4 expression (p=0.114). The 3-year disease-frese survival (DFS) was 65% and 50% in the low and high SOX2 expression (p=0.259), and 59% and 75% for low and high Oct4 expression (p=0.598). SOX2 expression was the only variable significantly associated with a lower OS and DFS on regression analysis. Our study demonstrated a trend toward improved OS and DFS with low SOX2 and high Oct4 expression in CSCC patients undergoing chemoradiotherapy.