Expression of ER, PgR, HER-2, and Ki-67 in core biopsies and in definitive histological specimens in patients with locally advanced breast cancer treated with neoadjuvant chemotherapy.

PURPOSE

Many studies have indicated that the response to therapy and the prognostic impact of a pathologic complete response after neoadjuvant treatment differ among breast cancer subtypes.

METHODS

The aim of our study is to evaluate the effect of this treatment on the expression of estrogen and progesterone receptors, human epidermal growth hormone receptor 2 and Ki67 in breast cancer. We identified 125 patients.

RESULTS

The estrogen receptor modified its expression from positive to negative in 8% patients and from negative to positive in 22%; progesterone in 21% and in 37% cases. Median Ki-67 value was 20.9% at biopsy and 18% after, HER-2 status did not show a remarkable change before or after neoadjuvant chemotherapy (NACT). We have identified a significant reduction in Ki-67 expression levels after chemotherapy in patients with a pathologic response. Detection of pretreatment Ki-67 could identify patients most likely to benefit from NACT.

CONCLUSIONS

NACT can change the status of ER, PgR, and Ki-67 expression in patients with breast adenocarcinoma, but it did not exert a significant effect on HER-2 status; HER-2 amplification appears to be more stable. We have identified a prognostic role for a decreased expression of PgR and Ki-67 after preoperative chemotherapy in breast cancer patients.