Abstract
Aim: To evaluate the relationship between apoptosis induced by chemotherapy and clinical response in breast cancer.
Methods: Apoptosis index (AI), mutant p53 and Bcl‐2 protein expression were evaluated in 44 breast tumour samples from patients submitted to neoadjuvant chemotherapy. Objective response (OR) to primary chemotherapy was observed in 37 patients (84%) and no response (NR) in seven. AI was measured by the rate of apoptotic cells identified using morphological criteria. p53 and Bcl‐2 protein expression were evaluated using an immunoperoxidase staining technique.
Results: The median AI change observed between pre‐chemotherapy AI and post‐chemotherapy AI was 0.84 in the OR group and 0.01 in the NR group, (rho = 0.4; p = 0.006). There was no change in Bcl‐2 protein expression following chemotherapy. In the OR group, p53 protein expression was positive in 41.6% of patients before and in 22.2% after chemotherapy (difference = 16.6%; p = 0.03). No change was detected in the NR group.
Conclusion: A positive correlation was found between the increase in AI and clinical response to neoadjuvant chemotherapy in locally advanced breast cancer.