Prognostic factors affecting disease-free survival rate following surgical resection of primary breast cancer.
In order to identify the prognostic factors that significantly influence the disease-free survival rate after surgical resection of primary breast cancers, we determined tumour and lymph node grades, and immunohistochemical staining for estrogen and progesterone receptors (ER and PR), c-erbB-2, p53, bcl-2, bax and PCNA in 76 patients. Univariate analysis showed that increased grade of tumour and lymph nodes, negative immunostaining for ER, positive immunostaining for c-erbB-2, and a high PCNA index (> or = 30%) negatively influenced the disease-free survival rate, but PR, p53, bcl-2 and bax had no predictive value. Although p53 was not an independent prognostic factor by itself, the combination of p53, bcl-2, and bax proved to correlate with the disease-free survival, with the best prognosis noted in tumours negative for p53 and positive for both bcl-2 and bax, intermediate prognosis in tumours negative for p53 and positive for either bcl-2 or bax and worst prognosis in tumors negative for p53 as well as bcl-2 and bax. Tumour grade correlated positively with PCNA index, while positive staining for ER correlated negatively with tumour grade as well as with PCNA index, although this was statistically insignificant. Immunostaining of breast cancers for bcl-2 correlated negatively with tumour grade and PCNA index. Immunostaining for c-erbB-2 correlated positively with PCNA but not with tumour grade. Immunostaining for p53 tended to correlate positively with PCNA, but not with tumour grade. Immunostaining for PR and bax did not correlate with tumour grade and PCNA index. These results suggest that in addition to tumour size and lymph node involvement, immunostaining for ER, c-erbB-2, and a high PCNA index are important prognostic factors in human breast cancer. Wild-type p53 with preserved bcl-2 and bax gene products is also a favorable prognostic factor indicating breast cancer at an early stage of cancer progression.