P53 expression correlates with low axillary tumor burden in breast cancer.

Background: The p53 mutation in breast cancer confers a worse prognosis and is usually associated with p53 overexpression (p53+) on immunohistochemistry. Previous studies have shown that p53+ tumors could be associated with low axillary tumor burden (ATB).

Objective: We aimed to evaluate the association between p53+ and ATB in a large series of breast cancers as an aid to personalizing axillary surgical treatment.

Methods: We retrieved 1762 infiltrating breast carcinomas from our database that were treated with upfront surgery in Hospital del Mar from 2004 to 2018. We compared p53+ and p53-negative (p53-) tumors in terms of the percentage of cases with high ATB and overall survival. This comparison was made overall and for each immunophenotype.

Results: Overall, 18.7% of breast tumors were p53+. High ATB was less common in p53+ tumors than in p53- tumors in the luminal B-Her2-negative immunophenotype (6.2% versus 16.9%, respectively, P = 0.025), but not in the other immunophenotypes or overall. Overall survival was worse in patients with p53+ breast cancer (P = 0.002).

Conclusion: p53+ breast cancers were associated with worse overall survival. However, low ATB was more common in these tumors than in p53- tumors in the luminal B-Her2-negative subtype. Information on p53 expression could be of use to predict ATB in some breast cancer tumors.