Nitric oxide synthase variants and disease-free survival among treated and untreated breast cancer patients in a Southwest Oncology Group clinical trial

Clin Cancer Res. 2009 Aug 15;15(16):5258-66. doi: 10.1158/1078-0432.CCR-09-0685. Epub 2009 Aug 11.


Purpose: Numerous chemotherapeutic agents are cytotoxic through generation of reactive species, and variability in genes related to oxidative stress may influence disease-free survival (DFS). We examined relationships between DFS and variants in NOS3, as well as NQO1, NQO2, and CBR3, among treated and untreated breast cancer patients in a Southwest Oncology Group clinical trial (S8897).

Experimental design: In the parent trial, women were assigned according to prognostic features; the high-risk group was randomized to cyclophosphamide, i.v. methotrexate, and 5-fluorouracil or to cyclophosphamide, i.v. doxorubicin, and 5-fluorouracil +/- tamoxifen, and the low-risk group did not receive adjuvant therapy. We extracted DNA from normal lymph node tissue and examined functional polymorphisms in NOS3, NQO1, NQO2, and CBR3, in relation to DFS, using Cox proportional hazard model.

Results: There were significant interactions between DFS, adjuvant therapy, and NOS3 Glu298Asp and -786 polymorphisms, alone and in combination (P for interaction = 0.008). When NOS3 genotypes were combined, women with genotypes encoding for lower nitric oxide who received chemotherapy had a >2-fold increase in hazard of progression (hazard ratio, 2.32; 95% confidence interval, 1.26-4.25), whereas there was reduced risk for those who did not receive adjuvant therapy (hazard ratio, 0.42; 95% confidence interval, 0.19-0.95). There were no associations between the other genotypes and DFS in either group.

Conclusion: Variants encoding lower activity of NOS3 may affect outcomes in breast cancer patients, with the direction of risk differing depending on chemotherapy status. These results may mirror the known dual functions of nitric oxide and nitric oxide synthase, depending on oxidative environment.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Algorithms
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Breast Neoplasms / diagnosis
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / genetics
  • Carcinoma / diagnosis
  • Carcinoma / drug therapy*
  • Carcinoma / genetics
  • Cisplatin / therapeutic use
  • Clinical Trials as Topic
  • Cyclophosphamide / therapeutic use
  • Disease-Free Survival
  • Doxorubicin / therapeutic use
  • Female
  • Fluorouracil / therapeutic use
  • Humans
  • Medical Oncology / methods
  • Methotrexate / therapeutic use
  • Middle Aged
  • Nitric Oxide Synthase Type III / genetics*
  • Polymorphism, Genetic / physiology
  • Prognosis
  • Southwestern United States


  • Doxorubicin
  • Cyclophosphamide
  • Nitric Oxide Synthase Type III
  • Cisplatin
  • Fluorouracil
  • Methotrexate

Supplementary concepts

  • CAF protocol
  • CMF protocol

Grant support