Does p53 immunoreactivity correlate with grade in phyllodes tumor of the breast? – A systematic review and meta-analysis

Evidence points to an association between p53 expression and breast phyllodes tumor (PT) grading. This study conducts a meta-analysis to investigate this association. Studies assessing PT and reporting p53 levels were identified up to December 2024, with a total of 539 cases. A meta-analysis was conducted for six studies that defined high p53 expression as ≥ 10% positive stromal cells. A separate analysis included four studies applying a ≥ 30% cutoff. When analyzing six studies with a 10% cut-off, significant association was found with increased p53 expression in 1) borderline PT when compared to benign PT (OR 7.22; CI 3.30 – 15.76; P < 0.001; I 2 = 0%); 2) malignant compared to borderline tumors (OR 2.48; 95% CI 1.11 – 5.51; P = 0.03; I 2 = 0%) and 3) malignant compared to benign PT (OR 16.39; 95% CI 5.98 – 44.92; P < 0.001; I 2 = 30%). When analyzing four studies adopting a cut-off point of 30%, significant association was found with increased p53 expression in 1) borderline PT when compared to benign PT (OR 2.77; CI 1.10 – 6.96; P = 0.03; I 2 = 0%); 2) malignant compared to borderline tumors (OR 5.71; 95% CI 2.27 – 14.40; P = 0.002; I 2 = 0%) and 3) malignant compared to benign PT (OR 18.98; 95% CI 7.02 – 51.31; P < 0.001; I 2 = 0%). Results demonstrate an association between p53 expression and higher tumor grade in PT. p53 expression was higher in borderline PT compared to benign tumors, and malignant PT compared to borderline tumors and further increased in malignant PT compared to benign tumors. Thus, p53 may help grading PT, especially in challenging cases.