FSTL1 and carcinoma: Therefore, secretion of FSTL1 by primary fibroblasts from normal bladder samples resulted in the expression level of FSTL1 being higher in normal bladder samples than in tumor samples, while the secretion of FSTL1 by cancer-associated fibroblasts (CAF) from the bladder tumors increases the carcinoma malignancy and decreases the prognosis of bladder cancer.