Alkaline phosphatase, placental-like 2 （ALPPL2, also known as ALPG） is a glycosylphosphatidylinositol （GPI）-anchored membrane protein and a member of the human alkaline phosphatase family. Typically not expressed in normal tissues except for the trophoblast, ALPPL2 shows a high tumor specificity. Immunohistochemical （IHC） analysis of tumor tissue arrays has revealed its expression in 43% of mesotheliomas, 60% of ovarian cancers, 36% of pancreatic cancers, 18% of gastric cancers, and 100% of seminomas.
ALPPL2 is not only a candidate for therapy development targeting ALPPL2-expressing tumors but has also been identified as a significant surface marker specific to the naive state of pluripotency, which is essential for both the establishment and maintenance of this state. Studies have demonstrated that the knockout of ALPPL2 can specifically impact the establishment, stability, and maintenance of naive pluripotency, confirming that the ALPPL2 protein is a functional molecular marker of the naive state surface.