APPLICATIONS OF SINGLE-COLOR AND DOUBLE-COLOR OLIGONUCLEOTIDE PRIMED IN-SITU LABELING IN CYTOLOGY

Interphase cytogenetics is mostly performed with use of fluorescence i n situ hybridization (FISH), using long DNA probes of several hundred or thousand base pairs in length Recently, oligonucleotide primed in s itu labeling (PRINS) was established for staining centromeres and telo meres of chromosomes in metaphase spreads by Taq-polymerase-mediated i ncorporation of labeled nucleotides. We investigated the use of PRINS in intact interphase cells of various cytologic preparations, targetin g chromosomes 1, 8, and 9. Examining cell smears (n = 3), touch prepar ations (n = 20), and cytospins (n = 11) of non-neoplastic and neoplast ic tissues, PRINS was as sensitive and reliable as the FISH method in assessing the exact chromosome number. Aneuploidy in tumor cells was c onfined by double-color PRINS in a part of the specimens. The PRINS re action, which requires heating of the cell preparations to as high as 96 degrees C, did not affect the cytomorphologic details. Because PRIN S is much faster and approximately 10 times less expensive than FISH, this method flows an increased application of interphase cytogenetics in diagnostic cytopathology.