THE PROGNOSTIC-SIGNIFICANCE OF AGNOR COUNTS AND PCNA-POSITIVE CELL COUNTS IN CANINE MALIGNANT-LYMPHOMAS

The behaviour of canine malignant lymphomas is difficult to predict on the basis of histomorphology alone, but the majority of such tumours are ''high-grade'' by most classifications. The aim of this study was to examine the prognostic significance of argyrophilic nucleolar organ izer region (AgNOR) counts and of proliferating cell nuclear antigen ( PCNA)-positive cell counts in canine malignant lymphomas; and to relat e the results to the histological grade (Kicl classification) and to t he survival time of treated and untreated dogs. Low- and high-grade ma lignant lymphomas differed significantly in having mean AgNOR counts o f 3.3 and 5.7 respectively. Untreated dogs with a mean AgNOR count hig her than 5.5 did not survive more than 85 days; the median survival ti me for this group was 38.5 days. Untreated dogs with a mean AgNOR coun t lower than 4.0 survived at least 82 days and one dog more than 300 d ays; the median survival lime for tills group was 154 days, Treated do gs with a mean AS NOR count higher than 5.5 did not sun ive more than 126 days; the median survival time for this group was 73.5 days. Treat ed dogs with a mean AgNOR count lower than 4.0 had a median survival t ime of 205.5 days and one dog survived 367 days. The mean AgNOR count would seem to be a valuable prognostic marker for canine malignant lym phomas, but PCNA counts had no prognostic significance in relation to the median survival time in treated or untreated dogs. (C) 1998 W.B. S aunders Company Limited.