High in Normal-1 also known as Uteroglobulin related protein 2 (UGRP2), is an 8kD secreted protein of the secretoglobin superfamily (SCGB3A1). HIN-1 is expressed in bronchial epithelial and secretory Clara cells, mammary epithelial cells (particularly during pregnancy), salivary glands, and the prostate. It is up-regulated in Clara cells by IL-4, IL-13, Oncostatin M, EGF, and TGF-a and down-regulated by IFNa B, and g. It is secreted into bronchial lavage fluid, saliva, and plasma and may form disulfide-linked dimers. HIN-1 binds to the macrophage scavenger receptor MARCO and to the surface of mammary and bronchial epithelial cells. HIN-1 promotes apoptosis and inhibits the proliferation, migration, and invasion of breast cancer cells likely through the Akt signaling pathway. The down-regulation of HIN-1 expression in many breast, lung, and prostate cancers correlates with hypermethylation of its promoter. Mature mouse HIN-1 shares 58% and 93% aa sequence identity with human and rat HIN-1, respectively. A variant of mouse HIN-1 has a substitution at the N-terminus in place of its potential signal peptide.