Background: Reverse transcriptase-polymerase chain reaction (RT-PCR) has been used to identify small numbers of tumor cells. Molecular detection is thought to provide useful information for the clinical management of postoperative adjuvant therapy regimens.
Objective: To use RT-PCR to identify messenger RNA (mRNA) coding for carcinoembryonic antigen, epithelial and variant CD44, and matrix metalloproteinase 7 in the portal venous and peripheral blood of patients with colorectal carcinoma to predict live or distant metastasis.
Design: Prospective consecutive series.
Setting: University hospital.
Patients and methods: Portal venous and peripheral blood samples were obtained from 22 patients with colorectal cancer during surgical manipulation. Using complementary DNA primers specific for carcinoembryonic antigen, CD44, and matrix metalloproteinase 7, RT-PCR was performed to detect tumor cells.
Main outcome measure: The clinical significance of RT-PCR for epithelial and variant CD44 mRNA in peripheral blood.
Results: During 3 years of follow-up, 2 patients whose peripheral blood had carcinoembryonic antigen and CD44 variant mRNA also had distant metastases (lung or spleen). Expression of epithelial and variant CD44 mRNA in peripheral blood was more highly correlated with the clinical cancer stage than with expression of carcinoembryonic antigen and matrix metalloproteinase 7.
Conclusions: Molecular detection of epithelial and variant CD44 mRNA in the peripheral blood may help determine distant metastases in patients with colorectal carcinoma. Molecular detection in the peripheral blood at surgical treatment suggests that systemic hematogenic tumor cell dissemination is an early event of distant metastasis.