Carcinoembryonic antigen 및 Cytokeratin 20 유전자 역전사중합효소연쇄반응을 이용한 복강내 위암세포의 검출

Abstract

위암환자의 복강내에 존재하는 소수의 암세포는 위절제술 후 재발의 중요한 원인이 되며 생존기간에도 영향을 미친다. 이러한 소수의 암세포의 검출에 종양표지자에 대한 역전사중합효소연쇄반응(reverse transcription polymerase chain reaction, RT-PCR)은 유용한 방법이다. Carcinoembryonic antigen (CEA)은 위장관암의 종양표지자로 널리 사용되어 왔고, 최근 Cytokeratin 20 (CK 20)이 위장관 조직, 요로상피 등의 조직에 국한된 표지자로 알려졌다. 본 연구에서는 1996년 7월부터 1997년 4월까지 원자력병원 외과에서 수술받은 위암 환자 79명을 대상으로 하였고, 이중 47명은 동일한 검체로 CEA 및 CK 20 유전자에 대한 RT-PCR(CEA RT-PCR, CK 20 RT-PCR)을 이용하여 복강내 위암세포를 검출하였으며 이외의 32명은 CK 20 RT-PCR으로만 검사하였다. 양성대조군으로 Colo 205 대장암세포주와 위암세포주인 MKN-45, SNU-5, SNU-16, Kato-III 세포는 CEA 및 CK 20 RT-PCR을 시행한 결과 모두 양성을 보인 반면에 음성대조군 10명의 골수는 음성이었다. 위암환자의 복강내 암세포를 검출하기 위한 CK 20 및 CEA RT-PCR의 양성률은 각각 27% 및 47%이었으며 세포학적 검사에 의한 양성률은 15%이었다. 암병기에 따른 CEA RT-PCR의 양성률은 stage I, 20%, stage II, 27%, stage III, 41%, stage IV, 79%이었고, CK 20 RT-PCR의 양성률은 stage I, 14%, stage II, 21%, stage III, 27%, stage IV, 35%로 위암의 병기에 따라 증가하였다. 결론적으로 CEA 및 CK 20 RT-PCR 방법은 위암 환자의 복강내 미세전이를 검출하는데 유용한 방법으로 판단된다. 이같은 방법의 사용은 암의 재발을 조기 진단하고, 화학 요법 등 치료 방침을 정하는 데 도움이 될 것으로 판단된다. ; A few cancer cells in peritoneal cavity may play a central role in tumor recurrence and would affect survival time for gastric cancer patients after surgical resection of cancer. Reverse transcription polymerase chain reaction(RT-PCR) for tumor associated antigen is a useful technique for the detection of small number of cancer cells. Carcinoembryonic antigen(CEA) have been widely used as a tumor marker for the gastrointestinal cancer. Recently Cytokeratin 20(CK 20) also has been known as a tissue specific marker confined to gastrointestinal tissue and urothelium. The subject of the study were 79 patients with gastric cancer who had surgical resection at the department of Surgery in Korea cancer center hospital from July 1996 to April 1997. Using RT-PCR targeting CK 20 and CEA mRNA, the cancer cells in peritoneal washing of 47 patients with gastric cancer were investigated. Additional 32 patients were examined by RT-PCR for CK 20 only. As a positive control, Colo 205 Colon cancer cell line, and gastric cancer cell lines such as MKN-45, SNU-5, SNU-16, Kato-III, were tested by RT-PCR for CEA and CK 20, and the PCR results were all positive in these samples. The bone marrow aspirates of 10 samples of negative controls were examined, and all samples showed negative result. The detection rate was 47% with the result of RT-PCR for CEA and 27% with the result of RT-PCR for CK 20. With the cytologic examination of the cancer cells of the peritoneal wash, the detection rate was 15%, and most of the positive cases were in stage IV and only one case was in stage III. The detection rate of RT-PCR for CEA was increased with the advances of tumor stage, the detection rate was 20% in stage I, 27% in stage II, 41% in stage III, and 79% in stage IV. With the result of RT-PCR for CK 20, the detection rate was 14% in gastric cancer stage I, 21% in stage II, 27% in stage III, and 35% in stage IV. In conclusion, RT-PCR for CEA and CK 20 would be a useful method for the detection of peritoneal dissemination of gastic cancer. There were a few cases tested positive with CK 20 only, this result indicates that the application of both markers would increase the detection rate of gastric cancer. These methods would be useful for the early detection for the recurrence of cancer and for the establishment of protocols of adjuvant chemotherapy. Further study for the prognosis of these patients and follow up study would be necessary.