Splice-site genetic polymorphism of the human kallikrein 12 (KLK12) gene correlates with no substantial expression of KLK12 protein having serine protease activity

Hum Mutat. 2004 Sep;24(3):273-4. doi: 10.1002/humu.9270.


The human kallikrein 12 (KLK12) gene is a new member of the KLK gene family, some members of which are implicated in the initiation and progression of cancer. In this study, we examined 50 non-cancerous tissues from Japanese patients with primary gastric cancer to determine the presence of genetic polymorphisms in the KLK12 gene using polymerase chain reaction (PCR)-single-strand conformation polymorphism and sequencing. Four different types of genetic polymorphisms were identified: one at a splice-donor site of intron 4 (c.457+2T>C), two in exon 6 (c.618_619delTG:p.Cys206fsX72 and c.735G>A:p.Met245Ile), and one in intron 3. The c.457+2T>C polymorphism was observed at a high frequency (allele frequency:0.63), compared to the frequencies of the two polymorphisms in exon 6 (allele frequency:0.01). Reverse transcriptase (RT)-PCR and Western blot analyses revealed that the c.457+2T>C polymorphism was associated with a splicing abnormality and that the expression of the human KLK12 protein (hK12), corresponding to the putative serine protease, was absent in individuals with a c.457+2C/C genotype but not in individuals with the T/T or T/C genotypes. We also found that recombinant His6-tagged hK12 has activity that cleaves chromogenic substrate (H-D-Pro-L-Phe-L-Arg-p-nitroaniline dihydrochloride), that is, serine protease activity. These results indicate that individuals with the c.457+2C/C genotype have no substantial expression of hK12 serine protease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma / enzymology
  • Carcinoma / epidemiology
  • Carcinoma / genetics
  • Cell Line
  • Chromogenic Compounds / metabolism
  • Enzyme Induction
  • Exons / genetics
  • Frameshift Mutation
  • Gastric Mucosa / enzymology
  • Genotype
  • Humans
  • Introns / genetics
  • Japan / epidemiology
  • Kallikreins / biosynthesis
  • Kallikreins / deficiency
  • Kallikreins / genetics*
  • Linkage Disequilibrium
  • Mutation, Missense
  • Polymerase Chain Reaction
  • Polymorphism, Genetic*
  • Polymorphism, Single-Stranded Conformational
  • RNA Splice Sites / genetics*
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Stomach Neoplasms / enzymology
  • Stomach Neoplasms / epidemiology
  • Stomach Neoplasms / genetics
  • Transfection


  • Chromogenic Compounds
  • RNA Splice Sites
  • RNA, Messenger
  • KLK12 protein, human
  • Kallikreins