Utility of the polymerase chain reaction in detection of gene expression in drug‐resistant human tumors

Recently, an enzymatic amplification method, the polymerase chain reaction (PCR), was modified to amplify a sequence of a drug resistance gene. The PCR assay can confirm data achieved by conventional molecular biology techniques, while requiring less time and fewer patient cells. It can be quantitated for gene expression. The data generated make it possible to analyze m-RNA expression in tumor samples without being limited to detecting only gene amplification in response to cancer chemotherapy. The PCR assay can be an effective device in the early detection of resistance to chemotherapy.