Further, it was noted that bladder cancer cell lines which express UGT1A (UDP-glucuronosyltransferase) enzymes were insensitive to resorcinol-based HSP90 inhibitors such as ganetespib and NVP-AUY922 (both UGT1A substrates), but sensitive to the ansamycin-based HSP90 inhibitors suggesting that intratumoral metabolism plays a role in drug resistance. This evidence concerns the gene UGT1A1 and urinary bladder cancer.