Increased p53 protein expression in malignant mammary phyllodes tumors

Abstract

The authors reviewed 143 cases (87 benign, 37 borderline, and 19 malignant) of mammary phyllodes tumors (PTs) and used immunohistochemistry to detect p53 protein product semi-quantitatively as negative, weak, moderate and strong (scored 0 to 3). For all PTs, an increasing trend of tumor size and malignancy was detected with increasing age. For p53 staining, 60 cases (42%) were negative, 55 (38%) stained weakly, 28 (13%) stained moderately, and 10 (7%) stained strongly. Of the 87 benign PTs, 41 (47%) were negative, 37 (43%) stained weakly, and 9 (10%) stained moderately. For the 37 borderline PTs, 16 (43%) were negative, 14 (38%) stained weakly, 6 (16%) stained moderately, and 1 (3%) stained strongly. Of the 19 malignant PTs, 3 (16%) were negative, 4 (21%) stained weakly, 3 (16%) stained moderately, and 9 (47%) stained strongly. The mean intensity score for p53 staining increased progressively from benign to borderline to malignant PT, with established statistical significance (P