Limitations of cytokeratin 20 RT-PCR to detect disseminated tumour cells in blood and bone marrow of patients with colorectal cancer: expression in controls and downregulation in tumour tissue

• Published in: Molecular pathology Vol. 55; no. 3; pp. 156 - 163
• Main Authors: Vlems, F A, Diepstra, J H S, Cornelissen, I M H A, Ruers, T J M, Ligtenberg, M J L, Punt, C J A, van Krieken, J H J M, Wobbes, Th, van Muijen, G N P
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and Association of Clinical Pathologists 01.06.2002; BMJ; BMJ Publishing Group Ltd; British Medical Journal Publishing Group
• Subjects: Biological and medical sciences; Biomarkers, Tumor - analysis; Biomarkers, Tumor - genetics; Biopsy; Blood; Bone marrow; Bone marrow examination; Bone Marrow Neoplasms - diagnosis; Bone Marrow Neoplasms - secondary; Cancer cells; Colorectal cancer; Colorectal Neoplasms - pathology; cytokeratin; cytokeratin 20; disseminated tumour cells; Down-Regulation; Evaluation; Gastroenterology. Liver. Pancreas. Abdomen; Growth; Humans; Intermediate Filament Proteins - analysis; Intermediate Filament Proteins - genetics; Investigative techniques, diagnostic techniques (general aspects); Keratin-20; Medical examination; Medical sciences; Metastasis; Miscellaneous. Technology; MNC; mononuclear cells; Neoplasm Metastasis; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; Neoplasm Staging; Neoplastic Cells, Circulating - chemistry; Original; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; PBGD; PBS; phosphate buffered saline; Physiological aspects; Polymerase Chain Reaction - methods; porphobilinogen deaminase; Quality Control; reverse transcriptase polymerase chain reaction; RNA, Messenger - genetics; RNA, Neoplasm - genetics; RT-PCR; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; Tumors; Netherlands; Performance evaluation; Human; Cytokeratin; Rectal disease; Carcinoma; Prognosis; Reverse transcription; Tumoral marker; Malignant tumor; Blood; Colonic disease; Polymerase chain reaction; Rectum; Bone marrow; Digestive diseases; Intestinal disease; Colon; Diagnosis; Technique; Molecular biology; Blood dissemination
• ISSN: 1366-8714; 1472-4154
• DOI: 10.1136/mp.55.3.156

Aims: Despite informative staging of patients with colorectal cancer, some patients with localised disease at diagnosis will develop recurrence or metastasis. Attempts to improve staging include sensitive detection of disseminated tumour cells in blood and bone marrow by reverse transcriptase polymerase chain reaction (RT-PCR). The results of this study have been considered in relation to the controversial results in the literature to elucidate the usefulness of cytokeratin 20 (CK20) RT-PCR to detect disseminated tumour cells further. Patients/Methods: Blood and bone marrow samples from 30 patients with colorectal cancer were studied by CK20 RT-PCR. Specificity was evaluated in 47 blood and 15 bone marrow samples from non-cancer controls. In addition, the expression of CK20 mRNA and protein was studied in normal and tumour colon tissue samples. Results: CK20 expression was detected in nine of 30 and nine of 19 of the blood and bone marrow samples from patients with colorectal cancer, respectively. In non-cancer control blood and bone marrow samples, CK20 expression was detected in 10 of 47 and four of 15, respectively. A difference between patient and control samples may be observed in terms of frequency of positive PCR tests. In tissue samples, CK20 mRNA expression was downregulated in tumour compared with normal colon tissue. Conclusions: CK20 expression was downregulated in tumour tissue compared with normal colon and a background expression of CK20 was seen in some control blood and bone marrow samples. Despite a lack of standardisation (which hampers comparison of studies), these results, together with other reports in the literature, suggest that CK20 may still be a suitable marker, but that background expression and threshold setting should be studied further.