CA9 and neoplasm: We performed IHC staining that showed the tumor cells in mass (I) diffusely and strongly expressed GATA3, MUC1, EMA, E-cadherin, 34bE12, Ksp-cadherin, CK7, and PAX-8 (Fig. 3a-e), while CD117, CAIX, CK20, RCC, and TFE3 were negative.