Solute carrier transporters, reduced folate carrier 1 and equilibrative nucleoside transporter 1, as immunohistochemical markers for high-grade malignancy in bladder cancer

Clinicopathological parameters derived from initial transurethral resection of bladder tumor (TUR-Bt) have limitations in predicting tumor progression in bladder cancer. Reduced folate carrier 1 (RFC1) and equilibrative nucleoside transporter 1 (ENT1) are solute carrier (SLC) transporters supporting cellular uptake of endogenous bioactive substances and anti-cancer drugs. The aim of this study was to elucidate the role of SLC transporters in bladder cancer and investigate the potential of RFC1 and ENT1 expression as immunohistochemical markers for high-grade malignancy. We compared T-stage with the immunohistochemical expression of RFC1 and ENT1 and other clinicopathological parameters; moreover, we also used multiple logistic regression model to assess relative contributions for T-stage in bladder cancer (n=130). Concurrently, 57 TUR-Bt-derived imprint cytological samples were stained to evaluate the implication of cytological analysis. Elevated expression levels of RFC1 and ENT1 were significantly correlated with higher T-stage (p < .0001) and efficiently predicted tumor progression, compared with other clinicopathological parameters (RFC1, p = .0325; ENT1, p = .0171). Independent variables of optimal model for predicting T-stage were gender, age, histological grade, expression levels of RFC1 and ENT1. Cytological analysis was consistent with immunostained-tissue data. We reveal RFC1 and ENT1 as potential immunohistocytochemical markers for high-grade malignancy in bladder cancer