Detection of colorectal cancer cells in peripheral blood by reverse-transcriptase polymerase chain reaction for cytokeratin 20

Abstract

The staging of colorectal cancer currently depends on pathological examination of the surgical specimen and regional lymph nodes, accompanied by imaging tests such as computed tomography (CT) scanning. However, alternative molecular methods to detect circulating tumour cells in blood or bone marrow may provide additional information about the extent of disease and prognosis. We have previously reported the development of a reverse‐transcriptase polymerase chain reaction (RT‐PCR) for cytokeratin 20 (CK 20) mRNA to detect circulating epithelial tumour cells. In this study, we report on the application of this method for detecting circulating tumour cells in patients with colorectal cancer. Using this method, CK 20 mRNA was detected in 8/8 human colorectal cancer cell lines, in 8/9 biopsies from primary colorectal tumours and in 9/10 biopsies of liver metastasis in patients with metastatic colorectal cancer, suggesting that CK 20 may be a useful target for the detection of circulating tumour cells in this patient group. In spiking experiments, 10 cells were consistently identified in 2 ml of whole blood (1 × 106–1 × 107mononuclear cells). In 12/25 (48%) peripheral blood samples from patients with known metastatic colorectal cancer, CK 20 mRNA was detected. However, there was no correlation between the detection of CK 20 mRNA in the peripheral blood and disease progression and survival in this group of patients. CK 20 mRNA was detected in 1/12 normal blood samples, which raises questions about the absolute specificity of CK 20 expression. Int. J. Cancer (Pred. Oncol.) 79:288–293, 1998.© 1998 Wiley‐Liss, Inc.

Cytokeratin 20 and guanylyl cyclase C mRNA is largely present in lymph node and liver specimens of colorectal cancer patients

“…However, the detection of CEC or DTC does not necessarily coincide with a poor outcome: Less than 50% of patients with known colorectal cancer metastasis were positive for CEC or DTC in peripheral blood as assessed by RT‐PCR for CK20 40. Also, in colorectal cancer patients staged N0 by routine pathohistology no difference in survival was detected between patients found CEC or DTC positive or negative in lymph nodes by immunohistochemistry for markers CK8/CK18 41…”

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

“…CK20 mRNA has been detected in most of the primary colon tumours and liver metastases; however, the number of tested samples was low and a highly sensitive CK20 RT-PCR was used. 45 Another study showed that the CK20 protein is expressed, but that the mRNA is downregulated in colorectal tumour tissue compared with normal colon mucosa. 29 Our data on CK20 mRNA expression in 13 normal and 18 tumour samples support these results by showing a lower degree of CK20 mRNA expression in tumour tissue compared with normal mucosa (fig 2).…”

Basic techniques in endoscopic ultrasound-guided fine needle aspiration for solid lesions: Adverse events and avoiding them

“…[5253545556575859606162] Others report a lack of correlation between tumor seeding and clinical outcomes. [63646566]…”