Modified interphase cytogenetics technique as an adjunct in the analysis of atypical cells in body fluids

Our objective was to determine the value of a modified interphase cytogenetics technique (MICT) by fluorescence in situ hybridization (FISH) in the study of atypical cells in body fluids in previously stained slides, allowing a direct morphologic-cytogenetic correlation. Thirty-five cases (29 bladder washes, four pleural fluids, two ascitic fluids) initially diagnosed as "atypical" with subsequent histologic confirmation were included. Histologically, there were 25 malignant four dysplastic, and six benign lesions. Previously Papanicolaou or Diff-Quick-stained slides were marked to determine the location of the cells of interest prior to FISH analysis. A pretreatment modification using pepsin digestion was utilized. Chromosome-specific probe 8 (Vysis) was used to detect numerical chromosomal abnormalities (NCA) involving chromosome 8. Various NCA (aneuploid) were detected in the atypical cells of histologically proven malignant cases but not in the benign cases. Using histology as a "gold standard," FISH has a sensitivity of 83% and a specificity of 100%. In conclusion this study shows that a MICT by FISH on previously stained slides can serve as an adjunct in the study of atypical cells in body fluids. This technique allows a direct morphologic-cytogenetic correlation which in the future may aid in the better understanding of carcinogenesis.