Quantitative analysis of folylpolyglutamate synthetase gene expression in tumor tissues by the polymerase chain reaction: marked variation of expression among leukemia patients.

Evidence from previous in vitro studies indicates that the enzyme folylpolyglutamate synthetase (FPGS) may be an important determinant of the antitumor activity of antifolate drugs that are substrates for this enzyme. To facilitate investigations regarding the association between FPGS content of tumor tissues and the sensitivity of tumors to antifolates, we developed a polymerase chain reaction (PCR)-based gene expression quantitation assay for measuring relative amounts of FPGS mRNA in tumor tissue specimens. From the known sequence of the human gene, FPGS-specific PCR primers were chosen that flanked a 263-base segment of the FPGS gene.