IMMUNOHISTOCHEMICAL STAINING FOR DNA TOPOISOMERASE-II IN NON-HODGKINS-LYMPHOMAS

DNA topoisomerase II (topo II) is the target of several clinically use ful anticancer drugs, Several of these agents, such as doxorubicin and etoposide (VP-16), are used to treat non-Hodgkin's lymphomas (NHL). T o understand the therapeutic selectivity of these drugs, a series of 3 3 cases of NHL for topo II were analyzed using an immunohistochemical technique that detects the enzyme in formalin-fixed, paraffin-embedded tissue, The average topo II index of high grade (Working Formulation) NHL was 48.6 with a range from 24.4 to 79.7, The average topo II inde x of low grade (Working Formulation) NHL was 4.4 with a range from 0.9 to 11.2, These two values are statistically different (P < .01). The intermediate grade (Working Formulation) NHL are a heterogeneous group based on topo II staining. The average topo II index value for the in termediate grade neoplasms was 26.7 with a range from 1.4 to 54.9. Bec ause the proliferation marker Ki-67 has been shown to be of prognostic importance when used in the analysis of NHL, 27 cases For also were a nalyzed for MIBI (Ki-67). The average MIB1 index of the high grade NHL was 59.8 with a range from 40.7 to 80.3, This average is statisticall y different (P < .01) than the average MIB1 index of 11.2 (range 1.7-2 8.3) found in the low grade NHL. Similar to results with topo II, the intermediate grade NHL was a heterogeneous group of tumors with respec t to MIB1 staining and had an average MIB1 index of 49.1 with a range from 8.9 to 86.7. These results show that high grade NHL have topo II and MIB1 indices that are significantly higher than low grade NHL. Int ermediate NHL are more heterogeneous and have topo II and MIB1 indices that range from low to high.