Expression of p53 and bcl-2 in correlation to clinicopathological parameters, hormone receptor status and DNA ploidy in breast cancers

The expression of p53 and bcl-2 was immunohistochemically investigated in 61 formalin-fixed, paraffin-embedded invasive breast carcinomas. The study was aimed to elucidate the relationship between both markers and the correlation of p53 and bcl-2, respectively, to clinicopathological variables, to hormone receptor status and to DNA-ploidy. Twenty tumors showed a positive reaction with the monoclonal antibody DO-1 against p53 protein. Its immunohistochemical demonstration was significantly correlated with a tumor size larger than 2 cm, a low estrogen receptor status and DNA-aneuploidy. Bcl-2 was demonstrated in 51 breast cancers. Bcl-2 was preferably seen in low grade and hormone receptor positive tumors. We found a negative correlation between the immunoreactive scores of p53 and bcl-2, but in 17 carcinomas a coexpression of both proteins was seen. Cases with this coexpression did not differ significantly from the other tumors in clinicopathological parameters. In eight of these cases more than 10% of the cells were found to be positive for both markers. in four cases we could show many cells to exhibit both markers as it was assessed by an immunofluorescence double labeling technique.