PROLIFERATING CELL NUCLEAR ANTIGEN (PCNA) IN NON-HODGKINS-LYMPHOMAS -CORRELATION WITH WORKING FORMULATION AND KIEL CLASSIFICATION IN FORMALIN-FIXED PARAFFIN-EMBEDDED MATERIAL

PCNA is a 36-KD proliferating cell nuclear antigen associated with the cell cycle. The immunocytochemical detection of PCNA represents a use ful tool for the study of tumor proliferation activity. This study doc uments the detection of PCNA, using antibody PC 10 in formalin-fixed, paraffin-embedded tissue, and correlates the proliferative activity of the non-Hodgkin's lymphomas (NHL) with histological grading assessed by the International Working Formulation (WF) and Kiel classification. In 92 cases of NHLs we found a strong correlation between the PCNA in dex and lymphoma grading. Statistically significant differences were a lso found between the proliferative index (PI) in low and high grade l ymphomas according to the Kiel classification (t = 9.519; p < 0.001) a nd between low, intermediate and high grade lymphomas according to the WF classification (F = 79.01; p < 0.001). In the Kiel classification the mean of low grade lymphomas was 39.5% and of high grade 75.7%. In the WF the average of low grade lymphomas was 29.7%, intermediate 53.1 % and high 75.1%. Although the differences among the groups had been s ignificant, we found variations inside each histological subgroup in b oth classifications. The intermediate lymphomas were the most heteroge neous group, with PI inside the same histologic subtypes coincident wi th low and high grade lymphomas. Since PCNA may be used as a marker of cell proliferation in clinical studies to estimate the biological agg ressiveness of lymphomas, its determination in intermediate grade NHL could be very useful to evaluate individual cases in this group and de termine prognosis and probably the appropriate therapy.