The detection of disseminated tumor cells in bone marrow from colorectal-cancer patients by a cytokeratin-20-specific nested reverse-transcriptase-polymerase-chain reaction is related to the stage of disease

Int J Cancer. 1996 Aug 22;69(4):278-82. doi: 10.1002/(SICI)1097-0215(19960822)69:4<278::AID-IJC7>3.0.CO;2-U.


The dissemination of cancer cells is a prerequisite in the development of micrometastases and solid metastases. Our previous examinations of these cells were based on immunocytological staining of tumor-associated antigens and cytokeratins. We have now developed a highly sensitive and specific detection method based on a nested reverse-transcriptase-polymerase-chain reaction (RT-PCR) of cytokeratin-20 (CK-20) mRNA. Using this method, we examined the bone marrow of 57 patients with colorectal cancer and detected increasing numbers of CK-20-positive samples, depending on the UICC stage. Some 35% of all bone-marrow samples tested positive for CK-20: none were found in colorectal cancer stage 1, 24% were in stage II, 31% in stage III and 71% in stage IV. Investigation of bone-marrow specimens of patients with pancreatic cancer showed that 4 out of 11 patients were positive for CK-20 mRNA. To confirm that sample positivity for CK-20 expression was due to disseminated tumor cells, we examined bone marrow from a control group (n = 16) without apparent carcinoma. In this group, 15 out of 16 donors were CK-20-negative, while one donor with familial adenomatous polyposis showed a CK-20-specific signal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Biomarkers, Tumor
  • Bone Marrow / pathology*
  • Colorectal Neoplasms / chemistry
  • Colorectal Neoplasms / pathology*
  • Gastrointestinal Neoplasms / chemistry
  • Gastrointestinal Neoplasms / pathology
  • Humans
  • Intermediate Filament Proteins / genetics*
  • Keratin-20
  • Molecular Sequence Data
  • Neoplasm Metastasis*
  • Neoplasm Staging
  • Polymerase Chain Reaction*
  • RNA, Messenger / analysis*
  • RNA-Directed DNA Polymerase
  • Tumor Cells, Cultured


  • Biomarkers, Tumor
  • Intermediate Filament Proteins
  • KRT20 protein, human
  • Keratin-20
  • RNA, Messenger
  • RNA-Directed DNA Polymerase