P40

P40 is a subtype of nuclear transcription factor P63, which can maintain cells in undifferentiated state with regenerative potential by inhibiting the expression of cell differentiation genes, participating in tissue development and repairing. P40 has high specificity in labeling squamous epithelium. And unlike P63, it has no cross reactivity in adenocarcinoma and lymphoma. Therefore, P40 has become one of the main biomarkers for the clinical diagnosis of squamous cell carcinoma in head, neck, esophagus, cervix and other areas, and its expression level is positively correlated with the cancer malignancy. This may be because P40 participates in the tumor development by promoting epithelial-mesenchymal transition (EMT). Among them, the combination of P40 and lung adenocarcinoma biomarkers has played an important guiding role in the differential diagnosis of lung squamous cell carcinoma. However, some scholars find that the co-expression of P40 and TTF-1, which is used to label lung adenocarcinoma, is present in some non-small cell lung cancers, providing a new research direction for the pathogenesis of lung tumors.