Predictive role of midtreatment changes in survivin, GSTP1, and topoisomerase 2α expressions for pathologic complete response to neoadjuvant chemotherapy in patients with locally advanced breast cancer.

INTRODUCTION

The primary aim of this study is to investigate the effect of change in the expression levels of survivin, glutathione-S-transferase P1 (GSTP1), and topoisomerase 2α (TOP2A) on the response to antracyclin-based and taxane-based neoadjuvant chemotherapy.

METHODS

This study included 32 locally advanced breast cancer patients. Tumoral expressions of survivin, TOP2A, and GSTP1 in serial biopsy specimens obtained before treatment, after sequential 4 cycles of doxorubicin+cyclophosphomide, and 4 cycles of docetaxel were analyzed by real-time polymerase chain reaction. Survivin expressions were additionally analyzed in serial blood samples.

RESULTS

The pathologic complete response (pCR) rate and the overall response rate (clinical complete and partial) were 28% (n=9) and 91% (n=29), respectively. There were no statistically significant correlations between serial TOP2A expression levels and response. There was a nonsignificant trend toward an improved response rate with decreased survivin expression. A significant decrease in the GSTP1 expression level throughout treatment (P=0.014), which was also shown to be significantly correlated with a pCR (P=0.0001), was seen. Downregulation of GSTP1 after 4 cycles of anthracycline-based combination was independently associated with improved progression-free survival (P=0.01).

CONCLUSIONS

Downregulation of GSTP1 is a significant predictor of pCR and improved progression-free survival during anthracycline-based and taxane-based neoadjuvant chemotherapy in patients with locally advanced breast cancer.