Objective: To demonstrate expression and single nucleotide polymorphisms (SNP) of human kallikrein 10 (KLK 10) in colorectal cancer (CRC) and to correlate the KLK 10 expression level with clinicopathological factors of CRC.
Methods: KLK 10 expression in 63 cases of tumoral and nontumoral colorectal tissues at the mRNA and protein levels were evaluated by quantitative real-time RT-PCR (qRT) and Western blot methods. KLK 10 protein was localized by immunohistochemistry. The KLK 10 genomic DNA from 16 cases of paired normal and cancerous colorectal tissues was PCR-amplified and examined for SNP by direct sequencing.
Results: The KLK 10 mRNA expression was detected by qRT in 61 of 63 (97%) CRC specimens. The KLK 10 expression was much higher in tumor tissue than in the corresponding normal mucosal tissue at the mRNA and protein levels. The KLK 10 mRNA expression level significantly correlated with the lymphatic invasion (P < 0.05) and clinical stage of CRC (P < 0.05). No mutations or polymorphisms were detected in exon 1, 2 and 5 of KLK 10 gene in CRC. A SNP in codon 50 of exon 3, GCC (alanine) to TCC (serine) was identified. The genetic changes of exon 4 were located at codon 106 [GGC (glycine) to GGA (glycine)], codon 112 [ACG (threonine) to ACC (threonine)], codon 141 [CTA (leucine) to CTG (leucine)], and codon 149 [CCG (proline) to CTG (leucine)]. All these SNP were identical in tumor as well as the corresponding normal tissue DNA from the same individuals.
Conclusions: The KLK 10 expression is up-regulated in CRC and higher expression of KLK 10 closely correlate with advanced disease stage, which predicts a poorer prognosis, however, further follow-up study is needed.