Secretoglobin Family 3A, Member 1 (SCGB3A1)

Breast cancer progresses from atypical hyperproliferation to in situ and then invasive carcinomas before culminating in metastatic disease. Ductal carcinoma in situ (DCIS) is thought to be the precursor of invasive ductal carcinoma. The deduced 104-amino acid HIN1 protein contains a signal peptide and is conserved in several species. HIN1 was highly expressed in breast tissue from a woman in the twenty-fifth week of pregnancy. In situ hybridization analysis confirmed the expression of HIN1 in small ducts and lobules, irrespective of their proliferation and hormone receptor status. HIN1 was also highly expressed in other tissues with branching ductal epithelia. No expression was detected in large or DCIS ducts. Western blot analysis showed expression of an 8-kD protein.