Calretinin(CR) is an intracellular calcium binding protein. During the cerebellum development, immunohistochemical tests discovered that Calretinin began to be weakly expressed in purkinje cells, blue cells and dentate nucleus neurons in the later stage (after 21 weeks of gestation). The staining intensity increased with the development of cerebellum. Calretinin is also expressed in normal and neoplastic mesothelioma cells, Calretinin is used to diagnosis differential between epithelial malignant mesothelioma and malignant lung adenocarcinoma.