Some of these immunohistochemical studies have also demonstrated elevated levels of ERα expression in non-neoplastic urothelial tissues, compared with bladder tumors [36, 51, 53], in contrast to the findings in the PCR analysis (i. e. 2.77-fold stronger expression in tumors than in matched normal tissues) [29], as well as in low-grade/NMI tumors, compared with high-grade/MI tumors [36, 53]. This evidence concerns the gene ESR1 and urinary bladder neoplasm.