COMPARISON OF DNA CONTENT IN NON-HODGKINS-LYMPHOMA AS MEASURED BY FLOW-CYTOMETRY AND CYTOGENETICS

Specific cytogenetic changes such as t(14;18) and t(8;14) are associat ed with specific histologic subtypes of non-Hodgkin's lymphoma (NHL) a nd may predict disease outcome. Nonspecific cytogenetic changes includ e other structural rearrangements or numerical changes such as monosom ies and trisomies, which may cause changes in total cellular DNA conte nt. In many solid tumors, the presence of abnormal DNA content may be predictive of clinical behavior, NHL biopsies, however, contain normal (diploid) as well as abnormal cells, and DNA changes in the peridiplo id range are detectable by cytogenetic analysis, but not consistently by flow cytometry. In the present study, we performed flow cytometric and cytogenetic analysis of DNA on biopsies from 129 patients with non -Hodgkin's lymphoma (NHL). Cytogenetic studies were successful on 88 ( 68%) of the samples. There was 55% concordance between flow cytometric and cytogenetic techniques in detecting aneuploid DNA content, with t he majority of discrepancies occurring in the peridiploid range, We al so detected six samples which were aneuploid by flow cytometry, but di ploid by cytogenetics. We suggest that a reasonable approach to determ ine DNA content, as it relates to prediction of outcome in NHL, would be to combine data from both of these techniques and analyze the resul ts in terms of ranges of DNA rather than by categorizing as diploid ve rsus aneuploid.