反转录聚合酶链反应对Dukes A、B期大肠癌淋巴结微转移的检测(3)
作者：佚名； 更新时间：2014-12-13
患者采取更积极的治疗方案？是否也应该对检出微转移的Dukes A期患者进行化疗？较早应用RT-PCR技术开展研究的肿瘤如黑色素瘤，通过随访确实认为微转移的发生与肿瘤的复发和患者的预后有关［14］。但对于大肠癌，以上问题还需要大样本的研究和较长时间的随访才能得到答案。
当然，作为一种尚未被广泛应用的方法，RT-PCR法本身也有一定的不足和局限性。由于扩增目标为RNA，因此取材必须是新鲜组织，无法作回顾性研究，且技术要求较高，标本处理必须迅速，抽提和反转录时需预防RNA的降解，整个过程中要严格禁止标本间的交叉污染和基因组DNA的污染以避免假阳性结果的产生。但总的来看，它还是具有以下优点：(1) 只要选择适当的靶RNA和引物，具有很高的敏感性和特异性；(2) RT-PCR能反映标本的整体情况而非局部断面；(3) 操作方法固定易标准化，判断结果容易且准确，人为因素干扰少；(4) 检测时间较短，能在24～48h时内得出结果，同时可检测多个标本。只要具备基本条件的分子生物学实验室均能进行。同时，CK20 RT-PCR法除检测淋巴结外，也能对患者的血液、骨髓和腹膜腔的微转移灶进行检测，它将对临床处理提供更多的指导和参考，具有良好的应用前景。
【参考文献】
1 Bresalier RS. Malignant neoplasms of the large intestine. In： M. Feldman，L. S. Friedman，and M. H. Sleisenger，editors. Sleisenger and Fordtran’s gastrointestinal and liver disease. Philadelphia： W. B. Saunders，2002，2215-2261.
2 Gusterson B. Are micrometastases clinically relevant? Br J Hosp Med，1992，47(4)：247-248.
3 Tsavellas G，Patel H，Allen-Mersh TG. Detection and clinical significance of occult tumour cells in colorectal cancer. Br J Surg，2001，88(10)： 1307-1320.
4 Greenson JK，Isenhart CE，Rice R，et al. Identification of occult micrometastases in pericolic lymph nodes of Dukes(B colorectal cancer patients using monoclonal antibodies against cytokeratin and CC49： Correlation with long-term survival. Cancer，1994，73(3)： 563-569.
5 Cutait R，Alves VAF，Lopes LC，et al. Restaging of colorectal cancer based on the identification of lymph node micrometastases through immunoperoxidase staining of CEA and cytokeratins. Dis Colon Rectum，1991，34(10)： 917-920.
6 Adell G，Boeryd B，Franlund B，et al. Occurrence and prognostic importance of micrometastases in regional lymph nodes in Dukes(B colorectal carcinoma： An immunohistochemical study. Eur J Surg，1996，162(8)： 637-642.
7 Hayashi N，Ito I，Yanagisawa A，et al. Genetic diagnosis of lymph-node metastasis in colorectal cancer. Lancet，1995，345(8960)： 1257-1259.
8 Moll R，Zimbelmann R，Goldschmidt MD，et al. The human gene encoding cytokeratin 20 and its expression during fetal development and in gastrointestinal carcinomas. Differentiation，1993，53(2)： 75-93.
9 Dorudi S，Kinrade E，Marshall NC，et al. Genetic detection of lymph node micrometastases in patients with colorectal cancer. Br J Surg，1998，85(1)： 98-100.
10 Gunn J，McCall JL，Yun K，et al. Detection of micrometastases in colorectal cancer patients by K19 and K20 reverse-transcription polymerase chain reaction. Lab Invest，1996，75(4)： 611-616.
11 Moll R，Lowe A，Franke WW. Cytokeratin 20 in humun carcinoma. A new histodignostic marker detected by monoclonal antibodies. Am J Pathol，1992，140(2)： 427-447.
12 Gerhard M，Juhl H，Kalthoff H，et al. Specific detection of carcinoembryonic antigen-expressing tumor cells in bone marrow aspirates by polymerase chain reaction. J Clin Oncol，1994，12(4)：725-729.
13 Nakamori S，Kameyama M，Furukawa H，et al. Genetic detection of colorectal cancer cells in circulation and lymph nodes. Dis Colon Rectum，1997，40(10 suppl)： S29-S36.
14 Bostick PJ，Morton DK，Turner RR，et al. Prognostic significance of occult metastases detected by sentinel lymphadenectomy and reverse transcriptase-polymerase chain reaction in early stage melanoma patients. J Clin Oncol，1999； 17(10)： 3238-3244.
当然，作为一种尚未被广泛应用的方法，RT-PCR法本身也有一定的不足和局限性。由于扩增目标为RNA，因此取材必须是新鲜组织，无法作回顾性研究，且技术要求较高，标本处理必须迅速，抽提和反转录时需预防RNA的降解，整个过程中要严格禁止标本间的交叉污染和基因组DNA的污染以避免假阳性结果的产生。但总的来看，它还是具有以下优点：(1) 只要选择适当的靶RNA和引物，具有很高的敏感性和特异性；(2) RT-PCR能反映标本的整体情况而非局部断面；(3) 操作方法固定易标准化，判断结果容易且准确，人为因素干扰少；(4) 检测时间较短，能在24～48h时内得出结果，同时可检测多个标本。只要具备基本条件的分子生物学实验室均能进行。同时，CK20 RT-PCR法除检测淋巴结外，也能对患者的血液、骨髓和腹膜腔的微转移灶进行检测，它将对临床处理提供更多的指导和参考，具有良好的应用前景。
【参考文献】
1 Bresalier RS. Malignant neoplasms of the large intestine. In： M. Feldman，L. S. Friedman，and M. H. Sleisenger，editors. Sleisenger and Fordtran’s gastrointestinal and liver disease. Philadelphia： W. B. Saunders，2002，2215-2261.
2 Gusterson B. Are micrometastases clinically relevant? Br J Hosp Med，1992，47(4)：247-248.
3 Tsavellas G，Patel H，Allen-Mersh TG. Detection and clinical significance of occult tumour cells in colorectal cancer. Br J Surg，2001，88(10)： 1307-1320.
4 Greenson JK，Isenhart CE，Rice R，et al. Identification of occult micrometastases in pericolic lymph nodes of Dukes(B colorectal cancer patients using monoclonal antibodies against cytokeratin and CC49： Correlation with long-term survival. Cancer，1994，73(3)： 563-569.
5 Cutait R，Alves VAF，Lopes LC，et al. Restaging of colorectal cancer based on the identification of lymph node micrometastases through immunoperoxidase staining of CEA and cytokeratins. Dis Colon Rectum，1991，34(10)： 917-920.
6 Adell G，Boeryd B，Franlund B，et al. Occurrence and prognostic importance of micrometastases in regional lymph nodes in Dukes(B colorectal carcinoma： An immunohistochemical study. Eur J Surg，1996，162(8)： 637-642.
7 Hayashi N，Ito I，Yanagisawa A，et al. Genetic diagnosis of lymph-node metastasis in colorectal cancer. Lancet，1995，345(8960)： 1257-1259.
8 Moll R，Zimbelmann R，Goldschmidt MD，et al. The human gene encoding cytokeratin 20 and its expression during fetal development and in gastrointestinal carcinomas. Differentiation，1993，53(2)： 75-93.
9 Dorudi S，Kinrade E，Marshall NC，et al. Genetic detection of lymph node micrometastases in patients with colorectal cancer. Br J Surg，1998，85(1)： 98-100.
10 Gunn J，McCall JL，Yun K，et al. Detection of micrometastases in colorectal cancer patients by K19 and K20 reverse-transcription polymerase chain reaction. Lab Invest，1996，75(4)： 611-616.
11 Moll R，Lowe A，Franke WW. Cytokeratin 20 in humun carcinoma. A new histodignostic marker detected by monoclonal antibodies. Am J Pathol，1992，140(2)： 427-447.
12 Gerhard M，Juhl H，Kalthoff H，et al. Specific detection of carcinoembryonic antigen-expressing tumor cells in bone marrow aspirates by polymerase chain reaction. J Clin Oncol，1994，12(4)：725-729.
13 Nakamori S，Kameyama M，Furukawa H，et al. Genetic detection of colorectal cancer cells in circulation and lymph nodes. Dis Colon Rectum，1997，40(10 suppl)： S29-S36.
14 Bostick PJ，Morton DK，Turner RR，et al. Prognostic significance of occult metastases detected by sentinel lymphadenectomy and reverse transcriptase-polymerase chain reaction in early stage melanoma patients. J Clin Oncol，1999； 17(10)： 3238-3244.
