We performed DNA-ploidy analysis by flow cytometry (FCM) in patients with malignant lymphoma (ML). The subjects consisted of 732 patients who were suspected of having ML and underwent immunological examination by FCM and DNA-ploidy analysis between June 1997 and June 2007. Biopsy specimens or body cavity fluid samples were used for analysis. The amount of DNA was measured via dissolves with cytoplasmic membrane used the nonionic detergent TritonX-100 and staining with propidium iodide. The incidence of DNA-aneuploidy and DNA Index distribution were examined according to disease types. As a result, DNA-aneuploidy was not observed in reactive lesions but was detected in 35.1% of patients with B-ML and 25.3% of those with T/NK-ML. Thus, tumor proliferation could be detected by DNA-ploidy analysis in about 30% of patients with ML. The DNA Index was widely distributed from 0.83 to 2.34. However, the index was present near diploidy (1.00 ± 0.24) in 75% of the patients and near tetraploidy (2.00 ± 0.24) in 20%. Since index concentration in areas near the G0/G1 and G2/M phases (95%) was observed, overlapping with their peaks may reduce the detection rate. Therefore, the selection of a high-resolution method and avoidance of the influences of aggregating cells are important.
