细胞角蛋白20、基质金属蛋白酶-7、-9在中低位直肠癌下切缘微转移的表达及相关性

Expression of creatine kinase 20, matrix metalloproteinase - 7 and matrix metalloproteinase - 9 in the micrometastasis in distal margin of middle and low rectal cancer

目的检测中低位直肠癌下切缘细胞角蛋白20（CK20）、基质金属蛋白酶（MMP）-7、MMP-9mRNA的表达，探讨下切缘微转移与临床病理特征的相关性及安全的下切缘距离。方法选取行全直肠系膜切除术的中低位直肠癌患者共50例，采用反转录-聚合酶链反应（RT—PCR）方法检测直肠癌标本下切缘CK20、MMP-7、MMP-9mRNA的表达。收集相关临床资料，随访肿瘤复发情况及时间。结果下切缘微转移组下切缘距肿瘤下缘的距离为（1．47±0．40）cm，下切缘无微转移组下切缘距肿瘤下缘的距离为（2．86±1.20）cm，差异有统计学意义（P〈0．05）。距离超过2．2cm的下切缘未见微转移。下切缘微转移组肿瘤的TNM分期、淋巴脉管侵犯、神经侵犯、淋巴结转移率及环周切缘（CRM）阳性率较无微转移组更高（P〈0．05），肿块直径更大（P〈0．05）；两组之间KRAS、NRAS基因突变及微卫星DNA不稳定性差异无统计学意义（P〉0．05）。结论直肠癌下切缘的微转移是术后复发的重要因素，中低位直肠癌患者的安全下切缘距离至少应为2．5cm。临床上对于分期较晚、病灶较大的患者，下切缘应该保证更安全的切缘距离。

Objective To explore the expression of creatine kinase 20 （ CK20）, matrix metallo- proteinase （MMP） -7 and MMP -9 in the micrometastasis in distal margin of middle and low rectal canc- er, and study the relationship between micrometastasis in distal margin and clinicopathological characteris- tics. Methods Fifty cases of middle and low rectal cancer were tested for CK20, MMP - 7 and MMP - 9 using reverse transcriptase - polymerase chain reaction （ RT - PCR）. Results The average distance was 1.47 ± 0.40 cm in distal margin with micrometastasis, but it was 2. 86 ± 1.2 cm in distal margin without micrometastasis （ P 〈 0.05 ）. TNM staging, lymphatic vascular invasion, nerve invasion, lymph node metastasis rate and rate of CRM in distal margin with mierometastasis were higher and tumor diameter was big- ger than distal margin without micrometastasis （P 〈 0. 05 ）. Between two groups, KRAS, NRAS mutation and microsatellite DNA instability had no obvious difference （ P 〉 0. 05 ）. Conclusion Distal margin with mierometastasis had effect on postoperative recurrence and metastasis in patients with middle and low rectal cancer. The safe distance of the patients with low rectal cancer in distal margin should be 2. 5 cm, and for patients with advanced disease, larger lesions, lymphatic vessels and nerve invasion, if the safe distance of 2. 5 cm can＇ t be guaranteed, preventive local radiotherapy postoperation is recommended to reduce local recurrence and metastasis.