IMMUNOHISTOCHEMICAL ANALYSIS OF BCL-2 AND P53 EXPRESSION IN BREAST CARCINOMAS - THEIR CORRELATION WITH KI-67 GROWTH FRACTION

We examined 59 breast cancers for p53 and bcl-2 protein expression by immunohistochemistry. The results were correlated with Ki-67 immunosta ining. p53-negativity was noted in 40 cases and the remaining 19 tumou rs were p53-positive. Thirty-six tumours showed strong expression of b cl-2 and in 23 no staining for this protein was observed. We found sta tistically significant reverse correlation between expression of p53 a nd bcl-2 in majority of carcinomas: 31 cases were bcl-2 positive and p 53-negative, and 14 tumours were bcl-2-negative and p53-positive. Six carcinomas showed no nuclear staining for Ki-67 and in the remaining 5 3 the percent of cancer cells positive for Ki-67 ranged from 1 to 60 ( mean: 14.6). In these 53 cases we found that bcl-2-positive tumours we re characterized by lower proliferation than bcl-2-negative tumours, t he mean value of Ki-67 immunostaining being 10.7% and 23.0%, respectiv ely. p53-negative tumours showed lower proliferation than p53-positive rumours: mean Ki-67 index was 10.2% and 23.9%, respectively. We concl ude that immunohistochemically detected p53 and bcl-2 proteins show a significant inverse relationship in majority of breast carcinomas and their expression correlates with tumour proliferation (Ki-67 immunosta ining).