Evaluation of hormone receptor, human epidermal growth factor receptor-2 and Ki-67 with core needle biopsy and neoadjuvant chemotherapy effects in breast cancer patients

BACKGROUND We investigated the reliability of core needle biopsy (CNB) in evaluating the status of hormone receptor (HR), human epidermal growth factor receptor (HER)-2, and Ki-67 status, and the effect of neoadjuvant chemotherapy (NAC) on the expression of these immunohistochemical markers. METHODS Among 177 patients with breast adenocarcinoma, 95 patients underwent NAC and the remaining 82 patients made up the control group. Immunohistochemistry (IHC) was used to evaluate the expression status of estrogen receptor (ER), progesterone receptor (PR), HER-2, and Ki-67 in the specimens obtained by surgical excision or CNB. RESULTS In the control group, the expression of ER, PR, HER-2, and Ki-67 was highly consistent between samples from surgical excision or CNB (all r > 0.8, P < 0.05). In the NAC group, the proportions of samples with changes in ER, PR, HER-2, and Ki-67 expression were 12.7%, 24.1%, 5.1%, and 38.0%, respectively; the figures in the control group were 2.4%, 4.9%, 2.4%, and 7.3%, respectively, which significantly differed in ER, PR, and Ki-67 (P < 0.05), but not HER-2 (P > 0.05). In the NAC group, pre- and post-treatment ER(+) rates did not significantly differ (P > 0.05), although PR(+) and high Ki-67 expression rates did significantly differ (P < 0.05). CONCLUSION Neither CNB nor surgical excision samples gave highly consistent results in HR, HER-2, and Ki-67 status. NAC can alter HR and Ki-67 status in breast adenocarcinoma patients. NAC decreased PR(+) rate and Ki-67 expression. The mean ER(+) rate exhibited a decreasing, but insignificant trend after NAC treatment. NAC had no significant effect on HER-2 expression.