CA9 and neoplasm: This mAb binds the tumor-associated antigen Carbonic Anhydrase 9 (CAIX), a transmembrane enzyme expressed by Renal Cell Carcinoma (RCC) and hypoxic tumor cells, while rarely found in healthy organs (Thiry et al., 2006; Genega et al., 2010; Santos Pacheco de Campos et al., 2022).