鸟苷酸环化酶C在大肠癌淋巴结中表达的意义

Significance of detecting GCC mRNA in regional lymph nodes from patients with colorectal cancer

目的:探讨在新鲜淋巴结组织检测鸟苷酸环化酶C(GCCmRNA)对大肠癌淋巴结微转移的诊断意义,以求更准确地评估大肠癌的转移情况。方法:收集本院2001.10～2002.3大肠癌根治术标本42例,计得淋巴结618枚;其中经病理形态学诊断无淋巴结转移者25例,得淋巴结370枚。用RT-PCR法检测GCCmRNA、CEAmRNA及CK20mRNA,分别以形态学证实转移淋巴结、良性大肠疾病淋巴结及正常大肠粘膜组织作为对照。全组病例随访6～26个月。结果:病例中临床分期为:DukesA期14例、B期11例、C期17例。总的阳性检出率为GCC22.65%(140/618)、CEA44.01%(272/618)、CK2043.69%(270/618);而在25例形态学诊断无转移病例中,三者的阳性率分别为12.16%(45/370)、42.16%(156/370)和41.62%(154/370)。25例常规病理阴性病例中14例检出GCCmRNA阳性淋巴结,其中4例出现复发转移,GCC诊断试验的灵敏度及特异度分别为100%、52.38%。淋巴结GCCmRNA阳性与复发/转移有统计学相关,影响无瘤生存率。结论:在传统病理形态学阴性的淋巴结中仍可能存在癌转移,用RT-PCR法检测微转移可提高淋巴结转移检出率,更准确地评估大肠癌患者的临床病理分期。GCCmRNA具有较好的特异性。

Objective To investigate the diagnostic significance of detecting colorectal cancer metastases in regional lymph nodes and to determine the metastases of tumor cells more accurately. Methods Six hundred and eighteen lymph nodes from 42 colorectal cancer patients undergoing radical operation were collected, including 370 lymph nodes from 25 cases which were histologically diagnosed to be node-negative. The nodes were submitted to RT-PCR examination. A specific marker guanylyl cyclase C(GCC) mRNA was used , together with CEA and CK20 mRNA. All the cases were followed-up for 6-26 months. Results Twenty-five out of 42 cases were determined to be of Dukes' A or B , while the others belonged to Dukes' C. GCC , CEA and CK20 mRNA were detected in 22.65%, 44.01% and 43.69% of 618 lymph nodes, respectively. Fourteen out of 25 cases histologically diagnosed to be node-negative had GCC-positive nodes, and of the 14 cases, 2 cases suffered from local recurrence and other 2 cases suffered from liver metastases. There was a significant association between mRNA levels and distant reccurence or metastasis. Conclusions There is a possibility that micrometastases may exist in histologically negative lymph nodes. It is helpful to probe the existence of micrometastases using RT-PCR , thus assessing more accurately the staging of the disease. GCC mRNA might also be a good marker for the detection of micrometastases in patients with colorectal cancer, but further researches are needed.