An early detection of recurrence using reverse transcriptase-polymerase chain reaction (RT-PCR) and methylation-specific polymerase chain reaction (MSP) from peripheral blood in patients after gastrectomy

摘要

Several molecular approaches, using peripheral blood of patients with cancers, have been assessed recently for ability to detect various primary and recurrent cancers at an early stage. One is the reverse transcriptase polymerase chain reaction (RT-PCR) analysis, which can detect a small number of circulating cancer cells. Another is the methylation-specific polymerase chain reaction (MSP), which detects tumor-specific alterations of cell-free serum DNA released from tumor into the circulation by necrosis and/or apoptosis. In the present study, we set out to assess the diagnostic value of the RT-PCR assay and the MSP assay for an early detection of recurrent diseases in patients after curative gastrectomy. Two of the 25 patients (8%) exhibited a CEA specific signal in their peripheral blood. On the other hand, seven patients (28%) showed aberrant methylation of the promoter region of at least one gene (3 patients for p16, 3 for E-cadherin, 3 for RARbeta genes, and 1 for CDH4 respectively). No abnormal signal was detected in sera from volunteers who served as controls. Of 10 patients who developed recurrences, a CEA-specific signal and aberrant methylation was demonstrated in plasma samples of 1 and 4 patients, respectively. One patient, without definite findings of recurrence at the time of analysis, developed recurrences 6 months later. Both assays can serve as markers that allow selection of those cases requiring more intensive screening and aggressive postoperative treatment.