SLC34A2 also known as NaPi2b, NPT2b is a pH-sensitive sodium-dependent phosphate transporter. Phosphate uptake is increased at lower pH. Mutations in the corresponding SLC34A2 gene causes pulmonary alveolar microlithiasis, a rare autosomal recessive disorder characterized by the deposition of calcium phosphate microliths throughout the lungs. Three transcript variants encoding two different isoforms have been found for SLC34A2. Research studies show aberrant expression of SLC34A2 in various type of cancer, including ovarian, breast, and lung cancer. Chromosomal rearrangements involving SLC34A2-ROS1 are seen in gastric carcinoma and non-small cell lung cancer and result in the formation of a SLC34A2-ROS1 chimeric protein that retains a constitutive kinase activity.