KLK12 is a novel serine protease and a new member of the human kallikrein gene family - Differential expression in breast cancer

Kallikreins are a subgroup of serine proteases that are involved in the pos ttranslational processing of polypeptide precursors, Growing evidence sugge sts that many kallikreins are implicated in carcinogenesis. In rodents, kal likreins are encoded by a large multigene family, but in humans, only three genes have been identified, By using the positional candidate approach, we were able to identify a new kallikrein-like gene, tentatively named KLK12 (for kallikrein gene 12). This new gene maps to chromosome 19q13.3-q13.4, i s formed of five coding exons, and shows structural similarity to serine pr oteases and other known kallikreins, KLK12 is expressed in a variety of tis sues including salivary gland, stomach, uterus, lung, thymus, prostate, col on, brain, breast, thyroid, and trachea, We identified three splicing forms of KLK12 that are expressed in many tissues. Our preliminary results indic ate that the expression of KLK12 is downregulated at the mRNA level in brea st cancer tissues and is up-regulated by steroid hormones in breast and pro state cancer cell lines, This gene may be involved in the pathogenesis and/ or progression of certain cancer types and may find applicability as a nove l cancer biomarker, (C) 2000 Academic Press.