Biomedical Research

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Influence of different chemotherapy regimens on the expression of ER and Her-2

Objective: To investigate the influence of different chemotherapy regimens on the expression of Estrogen Receptor (ER) and Her-2.

Methods: Clinical pathology and the treatment of 78 patients with breast cancer were analyzed retrospectively, in which 39 were treated with Cyclophosphamide, Doxorubicin, Fluorouracil (CAF) regimen (group A), and the other 39 were treated with Docetaxel, Doxorubicin, Cyclophosphamide (TAC) Taxotere, regimen (group B). All of them were treated with chemotherapy for 4 cycles. The protein expressions of ER and Her-2 were compared before and after the therapy. The protein expressions of ER and Her-2 in different chemotherapy cycles and groups of patients were analyzed. The protein expressions of ER and Her-2 in different clinical stages were recorded.

Results: (1) After the neoadjuvant chemotherapy for 78 patients, the protein expression of ER decreased from (1.53 ± 0.16) to (1.29 ± 0.12), t=10.60, P=0.00; the protein expression of Her-2 decreased from (1.32 ± 0.07) to (1.13 ± 0.03), t=22.03, P=0.00. (2) In this study, there were 40 patients with chemotherapy cycles less than three weeks and 38 patients equal or more than three weeks. Comparing the protein expression of ER in patients with chemotherapy cycles equal or more than three weeks with that less than three weeks, which was respectively (1.41 ± 0.18) and (1.35 ± 0.16), t=1.56, P=0.12; comparing the protein expression of Her-2 in patients with chemotherapy cycles equal or more than three weeks with that less than three weeks, which was respectively (1.27 ± 0.05) and (1.29 ± 0.05), t=1.77, P=0.08. (3) After chemotherapy, the average protein expression of ER was (1.27 ± 0.14) in group A and (1.34 ± 0.18) in group B. Comparing A with B, t=1.92, P=0.06; the average protein expression of Her-2 was (1.31 ± 0.07) in group A and (1.30 ± 0.09) in group B. Comparing A with B, t=1.73P=0.09. (4) Of the 78 patients, 36 were in stage I to II and 42 were in stage III to IV; comparing the average protein expression of ER of patients in stage I to II with that in stage III to IV, which was respectively (1.29 ± 0.12) and (1.35 ± 0.18), t=1.70, P=0.09; comparing the average protein expression of Her-2 of patients in stage I to II with that in stage III to IV, which was (1.15 ± 0.07) and (1.18 ± 0.08) respectively, t=1.75, P=0.08.

Conclusion: The protein expressions of ER and Her-2 changed in breast cancer after chemotherapy. The protein expression of Her-2 in patients with longer chemotherapy cycles decreased when compared with that in patients with shorter chemotherapy cycles, while the expression of ER increased after chemotherapy. This may be attributed to the biological differences within the tumor tissue or the limited samples.

Author(s): Chaoyang Xu, Liwei Meng, Shan Hu, Yingchun Xu