Spread of colorectal cancer micrometastases in regional lymph nodes by reverse transcriptase-polymerase chain reactions for carcinoembryonic antigen and cytokeratin 20

J Surg Oncol. 1998 May;68(1):34-40. doi: 10.1002/(sici)1096-9098(199805)68:1<34::aid-jso8>3.0.co;2-m.


Background and objectives: Lymph node metastasis is known as a significant predictor of prognosis in colorectal cancer patients. Recently, reverse transcriptase polymerase chain reaction (RT-PCR) has been applied to detecting micrometastasis. To assess the risk of recurrence and accurately determine the spread of tumor cells, we examined lymph node micrometastases in a series of colorectal cancer patients.

Methods: We examined 202 lymph nodes obtained from 13 colorectal cancer patients who underwent curative operation and were histologically diagnosed to be node-negative, using RT-PCR to amplify mRNAs for two epithelial markers, carcinoembryonic antigen (CEA) and cytokeratin 20 (CK-20).

Results: All the cases, including early stage patients, had micrometastases. A total of 102 among 202 lymph nodes (50.5%) were positive for either CEA or CK-20, or both (47.0, 40.1, and 36.6% respectively). Positive lymph nodes were spread along the courses of vascular trunks as well as being located in more distant regions.

Conclusions: Even in histologically negative lymph nodes, there is a considerable possibility that micrometastases may exist. Their detection by RT-PCR may improve clinical staging and indications for cancer therapy. We should also take care in the choice of surgical approach.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / analysis*
  • Carcinoembryonic Antigen / analysis*
  • Colorectal Neoplasms / pathology*
  • Female
  • Humans
  • Intermediate Filament Proteins / analysis*
  • Keratin-20
  • Lymph Nodes / pathology*
  • Lymphatic Metastasis / diagnosis*
  • Male
  • Middle Aged
  • Neoplasm Invasiveness
  • Neoplasm Staging
  • Polymerase Chain Reaction / methods
  • RNA, Messenger / analysis


  • Biomarkers, Tumor
  • Carcinoembryonic Antigen
  • Intermediate Filament Proteins
  • KRT20 protein, human
  • Keratin-20
  • RNA, Messenger