Testis and very low level in placenta and in some uterus samples. Observed in 25-50% of tumor samples of melanomas, non-small-cell lung carcinomas, bladder, prostate and head and neck cancers. At least three different alleles exist. The allele defined by Arg-6 and Glu-89 is associated with a risk of gastric cancer. Belongs to the CTAG/PCC1 family.