TRPV6 plays a new role in predicting survival of patients with esophageal squamous cell carcinoma

Background: TRPV6 is over-expressed and promotes the proliferation and invasion in many cancers. The association between the expression of TRPV6 and clinical outcome in esophageal squamous cell carcinoma (ESCC) has not been studied yet. We aim to elucidate the role of TRPV6 in predicting prognosis of patients with ESCC. Methods: In the retrospective study, mRNA level of TRPV6 was examined in patients (N = 174) from Sun Yat-sen University Cancer Center (mRNA cohort) and protein level of TRPV6 was examined in patients (N = 218) from Linzhou Cancer Hospital (protein cohort). Statistical analysis was performed to test the clinical and prognostic significance of TRPV6. Results: TRPV6 was down-regulated in ESCC tissues and cell lines. Patients with downregulation of TRPV6 trended to have a higher rate of advanced pT stage in both mRNA cohort (P = 0.089) and protein cohort (P = 0.073), though not statistically significant. No significant association was observed between TRPV6 expression and disease-specific survival (DSS) in both two cohorts. However, stratified survival analysis based on the gender showed that in mRNA cohort, downregulation of TRPV6 was associated with an unfavorable 3-year DSS in patients with male (47.3 % vs 63.6 %, P = 0.027) and with favorable 3-year DSS in patients with female (66.7 % vs 43.0 %, P = 0.031). The result was confirmed in protein cohort. Male patients with downregulation of TRPV6 had a poor 3-year DSS (20.0 % vs 57.1 %, P < 0.001) while female counterparts showed an enhanced 3-year DSS (56.1 % vs 28.6 %, P = 0.005). Conclusion: TRPV6 is down-regulated in ESCC. As a predictive biomarker, TRPV6 plays a Janus-like role in predicting survival of male and female ESCC patients.