Surfactant Protein B (SP-B)

SP-B is a surfactant protein secreted by lung's type Ⅱ alveolar epithelial cells. It is expressed in normal lung type Ⅱ alveolar epithelial cells, but not in glandular epithelial cells and squamous epithelial cells of other tissues. SP-B is mainly used in the auxiliary diagnosis of lung cancer and the differential diagnosis of lung metastasis.