结直肠癌组织中激肽释放酶10基因的表达及其与临床及病理的关系

目的 探讨激肽释放酶10（KLK 10）基因在结直肠癌组织中的表达及其与结直肠癌临床及病理特征的关系。方法 采用荧光实时定量PCR技术,检测KLK 10 mRNA在63例结直肠癌患者癌及相应正常结直肠组织中的表达;采用免疫组织化学及免疫蛋白印迹法（western blot）定位及检测其蛋白表达。对16例结直肠癌及相应正常结直肠组织基因组DNA KLK 10基因的6个外显子进行直接测序,分析其单核苷酸多态性（SNP）。结果 97％（61／63）患者的结直肠癌组织中可检测到KLK 10mRNA表达,结直肠癌组织中KLK 10基因的表达量显著高于相应正常结直肠组织。KLK 10基因于结直肠组织中的表达与淋巴结转移及临床分期显著相关（P〈0．05）。79％（50／63）患者的结直肠癌组织中可检测到相对分子质量为30000的蛋白表达。结直肠癌组织中KLK 10基因外显子3第50密码子有丙胺酸（GCC）-丝氨酸（TCC）改变,其中25％（4／16）为野生型GCC,56％（9／16）为杂合型GCC／TCC,19％（3／16）为纯合型TCC。结直肠癌及相应正常结直肠组织中,KLK 10基因外显子4有4个密码子,即106甘氨酸（GGC）-甘氨酸（GGA）]、112苏氨酸（ACG）-苏氨酸（ACC）]、141亮氨酸（CTA）-亮氨酸（CTG）]及149脯氨酸（CCG）-亮氨酸（CTG）]为SNP;相应正常结直肠组织中未发现有体突变。结论 KLK 10基因在结直肠癌组织中为异常高表达,且与癌淋巴结转移与临床分期显著相关,是结直肠癌潜在的预后标记物。

Expression and single nucleotide polymorphisms of kallikrein 10 in colorectal cancer

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 106GGC(glysine) to GGA(glysine)], codon 112ACG(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.