DNA AMPLIFICATION FOR THE IN-VITRO DETECTION OF CANDIDA-ALBICANS IN HEAD AND NECK SQUAMOUS-CELL CARCINOMAS

DNA was extracted from whole cells of Candida albicans and digested wi th HindIII restriction enzyme. After electrophoresis in a segment of t he lane containing between 800 and 1200 base pairs (bp) of DNA fragmen ts, a 1,1-kilobase (kb) fragment was found that hybridizes to biopsied tumor cells from head and neck squamous cell carcinomas (SCC). From t he nucleotide sequence of the putative gene locus, primers were synthe sized for use in a polymerase chain reaction (PCR) with DNA extracted from 18 SCC of the upper aerodigestive tract. After 30 cycles of ampli fication all tumors were found to contain sufficient amplified DNA to be detected in polyacrylamide or agarose gels, In contrast, template D NA from lymph nodes and malignant lymphomas failed to generate positiv e signals under these conditions. However, samples of DNA obtained fro m head and neck SCC cells in vitro, Candida glabrata and Candida parap silosis after PCR were found to contain homologous sequences. Applicat ion of this technique to head and neck SCC biopsies may help to identi fy quickly the presence of concurrent candidal species.