INS and type 2 diabetes mellitus: Further complicating the picture, the T2DM drug pioglitazone (a thiazolidinedione that increases the body’s sensitivity to its own insulin) appears to mildly increase the risk of BCa incidence [28,29], while the biguanide metformin (which increases insulin sensitivity, reduces glucose production by the liver, and decreases the gut absorption of glucose) may reduce the risk of BCa recurrence and progression, such that it is undergoing clinical trials for the prevention of recurrence in NMIBC patients [10,30].