CA9 and renal cell carcinoma: The CK7/AMACR/CAIX triple immunomarker is recommended as the first panel for subtyping of renal epithelial tumors based on the essential speculation in the current survey of immunopanel expression in renal tumors: 1) the importance of CK7 for RCC subtyping as a primary universal cardinal immunomarker, 2) the broad spectrum of AMACR, and 3) the highly specific marker of CAIX.