NaPi2b, also known as SLC34A2, is a sodium-dependent phosphate transporter encoded by the SLC34A2 gene and is a member of the SLC34 family. It is an eight-transmembrane protein that plays a crucial role in phosphate homeostasis by facilitating the trans-epithelial transport of phosphate. NaPi2b is highly expressed in various cancers, including non-small cell lung cancer (NSCLC), ovarian cancer, and papillary thyroid carcinoma, making it a promising target for cancer diagnosis and therapy. In normal tissues, its expression is limited, which further highlights its potential as a therapeutic target. Functionally, NaPi2b is involved in dietary phosphate absorption in the small intestine and surfactant synthesis in lung alveoli.