TSC1 and renal cell carcinoma: GPNMB is however non‐specific, because it essentially reflects the underlying pathogenetic alterations in other tumours, such as TFE3 RCC and TFEB RCC, as well as in angiomyolipoma (AML), and other TSC‐mTOR pathway associated renal tumours (for example, EVT, eosinophilic solid and cystic (ESC) RCC, and RCC with fibromyomatous stroma).