Abstract

Background
: Anthracyclines are the standard agents used to treat patients with advanced breast carcinoma. Some molecules are reportedly associated with anthracycline resistance; however, there has been some controversy surrounding these claims. The gain or loss of certain molecules after chemotherapy can explain the discrepancies in the results.
Methods
: We evaluated the expression levels of the estrogen receptor (ER), p53, and bcl-2 in specimens obtained from twenty patients with advanced breast cancer before and after anthracyclinebased chemotherapy using immunohistochemistry (IHC). We also examined HER2/neu expression in these specimens using IHC and fluorescence in situ hybridization (FISH) analysis.
Results
: After chemotherapy, one of the twenty cases (5%) showed decreased ER expression, one (5%) showed decreased p53 expression, and one (5%) showed increased bcl-2 expression. IHC and FISH analysis in pre- and post-chemotherapy specimens showed that the expression of HER2/neu changed from equivocal to negative in one case (5%).
Conclusion
: Our results showed that the expression levels of HER2/neu, ER, p53 and bcl-2 remained stable after chemotherapy, although the statistical significance of these results may not be validated due to the small number of cases. We also suggested that the resistance to anthracycline-based chemotherapy might not be associated with the modification of these molecules.

• Keywords: Anthracyclines;Carcinoma, ductal, breast;Drug resistance, neoplasm;Neoadjuvant therapy;