Open Access

O6‑methylguanine‑DNA methyltransferase as a prognostic and predictive marker for basal‑like breast cancer treated with cyclophosphamide‑based chemotherapy

  • Authors:
    • Sayuri Isono
    • Makoto Fujishima
    • Tatsuya Azumi
    • Yukihiko Hashimoto
    • Yoshifumi Komoike
    • Masao Yukawa
    • Masahiro Watatani
  • View Affiliations

  • Published online on: March 20, 2014     https://doi.org/10.3892/ol.2014.1985
  • Pages: 1778-1784
Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )


Abstract

The O6‑methylguanine‑DNA methyltransferase (MGMT) protein protects cells from alkylating agents by removing alkyl groups from the O6‑position of guanine. However, its effect on DNA damage induced by cyclophosphamide (CPM) is unclear. The present study investigated whether MGMT expression was correlated with prognosis in patients with breast cancer that was managed according to a common therapeutic protocol or treated with CPM‑based chemotherapy. The intrinsic subtypes and MGMT protein expression levels were assessed in 635 consecutive patients with breast cancer using immunohistochemistry. In total, 425 (67%) luminal A, 95 (15%) luminal B, 47 (7%) human epidermal growth factor receptor‑2+/estrogen receptor- (HER2+/ER‑) and 48 (8%) basal‑like subtypes were identified. Of these, MGMT positivity was identified in 398 (63%) of 635 breast cancers; 68% of luminal A, 67% of luminal B, 30% of HER2+/ER‑ and 46% of basal‑like subtypes were positive. The overall survival (OS) and disease‑free survival (DFS) rates did not significantly differ according to the MGMT status among patients with luminal A, luminal B or HER2+/ER‑ subtypes, and patients with MGMT‑negative basal‑like cancers tended to have a longer DFS, but not a significantly longer OS time. CPM‑containing chemotherapy was administered to 26%, 40%, 47% and 31% of patients with luminal A, luminal B, HER2+/ER‑ and basal‑like tumors, respectively. Although the MGMT status and clinical outcomes of patients with the luminal A, luminal B or HER2+/ER‑ subtypes treated with CPM were not significantly correlated, the patients with MGMT‑negative basal‑like tumors who received CPM exhibited significantly improved DFS and OS compared with the CPM‑treated patients with MGMT‑positive tumors. MGMT may be a useful prognostic and predictive marker for CPM‑containing chemotherapy in basal‑like breast cancer.
View Figures
View References

Related Articles

Journal Cover

June-2014
Volume 7 Issue 6

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

Sign up for eToc alerts

Recommend to Library

Copy and paste a formatted citation
x
Spandidos Publications style
Isono S, Fujishima M, Azumi T, Hashimoto Y, Komoike Y, Yukawa M and Watatani M: O6‑methylguanine‑DNA methyltransferase as a prognostic and predictive marker for basal‑like breast cancer treated with cyclophosphamide‑based chemotherapy. Oncol Lett 7: 1778-1784, 2014
APA
Isono, S., Fujishima, M., Azumi, T., Hashimoto, Y., Komoike, Y., Yukawa, M., & Watatani, M. (2014). O6‑methylguanine‑DNA methyltransferase as a prognostic and predictive marker for basal‑like breast cancer treated with cyclophosphamide‑based chemotherapy. Oncology Letters, 7, 1778-1784. https://doi.org/10.3892/ol.2014.1985
MLA
Isono, S., Fujishima, M., Azumi, T., Hashimoto, Y., Komoike, Y., Yukawa, M., Watatani, M."O6‑methylguanine‑DNA methyltransferase as a prognostic and predictive marker for basal‑like breast cancer treated with cyclophosphamide‑based chemotherapy". Oncology Letters 7.6 (2014): 1778-1784.
Chicago
Isono, S., Fujishima, M., Azumi, T., Hashimoto, Y., Komoike, Y., Yukawa, M., Watatani, M."O6‑methylguanine‑DNA methyltransferase as a prognostic and predictive marker for basal‑like breast cancer treated with cyclophosphamide‑based chemotherapy". Oncology Letters 7, no. 6 (2014): 1778-1784. https://doi.org/10.3892/ol.2014.1985