Calvete J, Larrinaga G, Errarte P, et al. - Researchers assessed the role of cancer-associated fibroblasts (CAFs) in the prognosis of bladder cancer and its correlation with basal and luminal phenotypes. In a series of 121 patients with urothelial carcinoma (UC, a heterogeneous disease with dismal prognosis) of the bladder treated by radical cystectomy with lymph node dissection, clinical and pathological parameters, including the immunohistochemical expression of fibroblast activation protein (FAP) and markers of basal (CK5/6, CD44) and luminal (CK20, GATA3) phenotypes were examined and their involvement on long-term cancer-specific survival was assessed. Worse disease-specific survival was inferred by cytoplasmic immunostaining of FAP in CAFs. Along with the most suitable differentiation at T2a/T2b level, and with the negative expression of markers of luminal phenotypes, such as CK20 and GATA3, FAP expression was correlated with tumor staging. Simultaneous expression of FAP, CK5/6, and CD44 was a strong predictor of disease-specific survival, along with nodal invasion, and bladder infiltration up to deep muscle or beyond. In the primary tumors and nodal disease, no correlation between positive FAP expression was discovered. In high-grade invasive UC of the bladder with a basal phenotype, FAP expression in CAFs obliged tumor invasion. Thus, to prognosticate clinical behavior in these individuals, this new immunohistochemical marker could be summed up with the routine immunohistochemical protocol.