Shift in cytotoxic target from estrogen receptor-positive to estrogen receptor-negative breast cancer cells by trastuzumab in combination with taxane-based chemotherapy

  • Authors:
    • Mitsuhiro Hayashi
    • Kazuharu Kai
    • Yasuhiro Okumura
    • Tomofumi   Osako
    • Nobuyuki Arima
    • Hirotaka Iwase
    • Reiki Nishimura
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  • Published online on: January 11, 2011     https://doi.org/10.3892/ol.2011.232
  • Pages: 303-308
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Abstract

Trastuzumab has shown significant clinical benefits in patients with operable and metastatic HER2-positive breast cancer. However, the biological mechanism of the additional effect of trastuzumab administered in combination with conventional chemotherapy is poorly understood. We performed a retrospective analysis of 55 patients with HER2-positive breast cancer treated with anthracycline and taxane (chemotherapy alone; CT), or trastuzumab in combination with taxane-based chemotherapy (CT+T) for neoadjuvant chemotherapy. We determined the therapeutic efficacies [clinical (CR) and pathological complete responses (pCR)] and changes in the proportion of positive cells for each biomarker pre- to post-neoadjuvant chemotherapy for each treatment regimen. Clinical-CR and quasi-pCR rates defined as the absence of invasive tumors or only a few remaining invasive tumor cells were 6.9 and 31.0% in the CT group and 46.2 and 65.4% in the CT+T group, respectively. In the CT group, the proportion of estrogen receptor (ER)-/progesterone receptor (PgR)-positive cells decreased significantly following treatment (ER, 73.5 vs. 50.9%; P=0.02). Changes in the proportion of ER-/PgR-positive cells were not noted in the CT+T group (ER, 81.9 vs. 80.3%; P=0.61), although a relatively greater decrease in the proportion of Ki-67-positive cells was found in the CT+T group than that in the CT group (-26.5 vs. -13.7%). These findings indicate that CT+T inhibits ER-negative and Ki-67-positive breast cancer cells. In conclusion, trastuzumab sensitized ER-negative proliferative cells to cytotoxic chemotherapy. This finding may indicate an additional clinical effect of trastuzumab when administered in combination with conventional chemotherapy as neoadjuvant chemotherapy for HER2-positive breast cancer.
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March-April 2011
Volume 2 Issue 2

Print ISSN: 1792-1074
Online ISSN:1792-1082

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Spandidos Publications style
Hayashi M, Kai K, Okumura Y, Osako T, Arima N, Iwase H and Nishimura R: Shift in cytotoxic target from estrogen receptor-positive to estrogen receptor-negative breast cancer cells by trastuzumab in combination with taxane-based chemotherapy. Oncol Lett 2: 303-308, 2011
APA
Hayashi, M., Kai, K., Okumura, Y., Osako, T., Arima, N., Iwase, H., & Nishimura, R. (2011). Shift in cytotoxic target from estrogen receptor-positive to estrogen receptor-negative breast cancer cells by trastuzumab in combination with taxane-based chemotherapy. Oncology Letters, 2, 303-308. https://doi.org/10.3892/ol.2011.232
MLA
Hayashi, M., Kai, K., Okumura, Y., Osako, T., Arima, N., Iwase, H., Nishimura, R."Shift in cytotoxic target from estrogen receptor-positive to estrogen receptor-negative breast cancer cells by trastuzumab in combination with taxane-based chemotherapy". Oncology Letters 2.2 (2011): 303-308.
Chicago
Hayashi, M., Kai, K., Okumura, Y., Osako, T., Arima, N., Iwase, H., Nishimura, R."Shift in cytotoxic target from estrogen receptor-positive to estrogen receptor-negative breast cancer cells by trastuzumab in combination with taxane-based chemotherapy". Oncology Letters 2, no. 2 (2011): 303-308. https://doi.org/10.3892/ol.2011.232