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Updated: Aug 19, 2026
Semi-quantitative Detection of RNA-dependent RNA Polymerase Activity of Human Telomerase Reverse Transcriptase Protein
Published on: June 12, 2018
Detection of circulating tumour cells and nodal metastasis by reverse transcriptase-polymerase chain reaction
L S Wong1, J E Cantrill, S Odogwu
1Department of Surgery, Walsgrave Hospital NHS Trust, UK.
Background:
In the search for occult metastases in lymph nodes or circulating tumour cells, a reverse transcriptase-polymerase chain reaction (RT-PCR) assay was developed to detect tumour-specific splice variants of the transcript of the CD44 gene. The assay was highly sensitive and could detect ten tumour cell per 10(5) leucocytes.
Methods:
RNA was purified from peripheral blood (n = 24) and regional lymph nodes (n = 14) from patients with colorectal cancer. Complementary DNA was made and amplified using primers specific for the CD44 gene. Southern blotting with exon-specific probes was used to enhance the sensitivity.
Results:
Tumour cells were detected in peripheral blood samples in four patients and lymph nodes in nine, in one of whom conventional histology had not detected tumour cells.
Conclusion:
This technique may be useful in the early diagnosis of primary or metastatic tumours, in assessing prognosis and in detecting residual disease after treatment.
