DNA content and kinetic characteristics of non-Hodgkin's lymphoma: determined by flow cytometry and autoradiography.

The determination of DNA content and [3H]thymidine labeling index was carried out on malignant lymph nodes from 74 patients with non-Hodgkin's lymphoma. Analysis of cellular DNA content was performed using propidium iodide as DNA-specific fluorescence dye. The ploidy was expressed as the DNA ratio between the relative DNA content of the human lymphoid G0/1 cells to that of chicken red blood cells. Forty-five of the 74 non-Hodgkin's lymphomas (61%) were aneuploid populations and the majority of these (91%) showed a hyperdiploid DNA content. A higher frequency of aneuploidy (72%) was observed in tumors with unfavorable histology than in those with a favorable histology (55%). Moreover, among aneuploid lymphomas heterogeneous populations were observed in 24% of the cases. The evaluation of flow cytometric data using Fried's deconvolution procedure showed no statistically different frequency of G0/1, S and G2 + M cells between the two groups of tumors with favorable and unfavorable histology. on the contrary, a statistically different frequency of G0/1 and S cells was observed between the two groups of tumors with low and high labeling indices (P less than 0.01). A correlation was found between autoradiographic and flow cytometric determination of S phase cells (P less than 0.001).