Breast carcinoma in women under the age of 50: Relationship between p53 immunostaining, tumour grade, and axillary lymph node status.

There is evidence to suggest that breast carcinoma in young women behaves in a more aggressive manner than in older women. As positive immunostaining for p53 has also been associated with increased tumour aggressiveness, this study was aimed at finding out whether patients under the age of 50 years have a higher prevalence of p53 positivity in their tumours. The inter-relationships between age, p53, tumour grade, and axillary lymph node status were also investigated. Two hundred and twenty nine invasive carcinomas were studied. One hundred and eight patients were under the age of 50, and 121 were at or above that age. The specific p53 monoclonal antibody DO7 and the avidin-biotin complex immunoperoxidase technique were used. Fifty seven tumours (25 %) showed variable degrees of p53 positivity. The incidence of positivity was slightly higher in women under the age of 50 as compared with those at or above that age (29% (31/108) vs. 21% (26/121), respectively), but the difference was not statistically significant (p < 0.05). On the other hand, in invasive ductal carcinoma (191 cases), p53 positivity was significantly related to high tumour grade (7% in grade I [1/14], 19% in grade II [20/105], and 43% in grade III [31/72]; p < 0.0001 [I-II vs III]). p53 positivity was also significantly related to the presence of extensive (more than three) axillary lymph node metastases (p53 positivity being 22% in node negative tumours [40/178], 18% in tumours with three or less positive nodes [6/33], and 61% in tumours with more than 3 positive nodes [11/18]; p = 0.0033 [second vs third group]). Both features were also significantly more common in the younger age group. The results suggest that the slightly higher incidence of p53 positivity seen in tumours from younger patients, is probably related to the significantly higher incidence of grade III tumours in these patients.