KLK13 (kallikrein-related peptidase 13)

Kallikreins (KLKs) constitute a family of 15 homologous secreted serine proteases (KLK1-15), which participate in numerous physiological procedures. All KLKs are encoded by the largest contiguous cluster of protease genes in the human genome (19q13.3-13.4). In specific, the human KLK13 gene spans a region of 8905 nucleotides, comprises 5 exons and 4 intervening introns and produces a single mRNA transcript that encodes KLK13 precursor protein. Like the rest of the KLK genes, KLK13 gene encodes for a trypsin-like serine peptidase, the functions of which are still unclear. KLK13 expression has been detected in a variety of human tissues and is found to be associated with several types of cancer. Evidence has showed that KLK13 can be an independent biomarker of favorable prognosis in breast cancer patients and may potentially be able to identify patients likely to benefit from hormonal treatment. In addition, major prognostic abilities of KLK13 have been confirmed in nonsmall cell lung cancer as well as gastric cancer, as patients with KLK13 overexpression demonstrated significantly longer overall (OS) and disease-free survival (DFS) accordingly. Although the precise localization and structure of the KLK13 gene has now been fully identified, its functional roles and implication mechanisms to human malignancies are still not conveniently understood and merit further investigation