Association of insulin-like growth factor 1 receptor and estrogen receptor with pathological complete response to neoadjuvant chemotherapy in HER2-negative breast cancer.

PURPOSE: To investigate the association of insulin like growth factor 1 receptor (IGF-1R) and estrogen receptor (ER) with pathological complete response (pCR) secondary to neoadjuvant chemotherapy in human epidermal growth factor receptor-2 (HER2)-negative breast cancer.

MATERIALS AND METHODS: The immunohistochemical expressions of IGF-1R and ER were detected in puncture specimens from 273 patients who received neoadjuvant chemotherapy. Association of IGF-1R and ER expression with pCR to neoadjuvant chemotherapy was evaluated.

RESULTS: In 273 cases of breast cancer, the high expression rate of IGF-1R was 42.1% (115/273) and the ER-positivity rate was 63.0% (172/273). The positive rate of IGF-1R in ER-positive patients (51.2%) was significantly higher than that in ER-negative patients (26.7%; p < 0.01). Multivariate analysis showed that the numbers of chemotherapy circles, TNM stage and ER status were independent factors for pCR rate. The pCR rate in ER-negative patients (14.9%) was significantly higher than that in ER-positive patients (6.4%; p < 0.05). The pCR rate in patients with low and high expression of IGF-1R was 8.9% and 10.4%, respectively, which was not statistically significant (p > 0.05). Further analysis of the impact of IGF-1R expression status on the pCR rate in ER-positive subgroup did not show any significant associations. Similar results were found in the ER-negative subgroup (p > 0.05). In the high-IGF1R subgroup, the pCR rate was higher for ER-negative than that for ER-positive (25.9% vs. 5.7%) patients, which was statistically significant (p < 0.01), while in the low-IGF1R subgroup, there was no significant difference between ER-negative and ER-positive (10.8% vs. 7.1%, p = 0.42) patients. The pCR rate of ER-negative and high-IGF-1R expression (25.9%) patients was significantly higher than the overall pCR rate (p < 0.01).

CONCLUSION: ER-negative patients were more sensitive to neoadjuvant chemotherapy, and the pCR rate was significantly higher in ER-negative than in ER-positive patients in the high-IGF1R subgroup.