FLOW CYTOMETRIC DETECTION OF CHROMOSOME-ABNORMALITIES BY MEASURING CENTROMERIC INDEX, DNA CONTENT, AND DNA-BASE COMPOSITION

This paper highlights two improvements of the on-line centromeric inde x (CI) analysis for the detection of chromosome abnormalities. On-line CI versus DNA content analysis of an EBV-transformed cell line, with a deletion (11)(p13p15.1), of a patient with aniridia and Wilms' tumou r demonstrates the first improvement of the method of on-line CI analy sis for flow karyotyping and sorting; a reciprocal translocation, inse rtion, or deletion can, when the cell type contains not more than a fe w of these types of abnormalities, be traced to the p-arm or q-arm of the relevant chromosome. On-line CI analysis was also performed with c hromosomes isolated from a transitional cell carcinoma of the bladder. Cytogenetic analysis of this cell line showed numerous chromosomal ab normalities. Chromosomes of this cell line were also karyotyped by biv ariate flow cytometry using a different set of parameters: Hoechst 33 258 fluorescence intensity (HOfl) versus chromomycin A3 fluorescence i ntensity (CAfl). A comparison of these results reveals the second impr ovement of the CI method for the detection of chromosome abnormalities ; bivariate analysis of CI versus propidium fluorescence (PIfl) are co mplementary to bivariate analysis of HOfl versus CAfl. Chromosomes wit h distributions that fuse together in the HO/CA flow karyotype may be distinguished as individual peaks on the basis of their CI values.