Tissue specificity; Not expressed in normal tissues, except in germ cells in the seminiferous tubules and in Purkinje cells of the cerebellum. Expressed in various tumors, including melanoma, lymphoma, as well as pancreatic cancer, mammary gland cancer, non-small cell lung cancer and liver cancer. In hepatocellular carcinoma, there is a inverse correlation between tumor differentiation and protein expression, i.e. the lower the differentiation, the higher percentage of expression.