Association between the HER2 Ile655Val polymorphism and response to trastuzumab in women with operable primary breast cancer

Ann Oncol. 2014 Jun;25(6):1158-64. doi: 10.1093/annonc/mdu111. Epub 2014 Mar 7.

Abstract

Background: Human epidermal growth factor receptor 2 (HER2) Ile655Val polymorphism may affect the efficacy of trastuzumab treatment of breast cancer.

Patients and methods: HER2 Ile655Val polymorphism was determined in 4167 patients with primary breast cancer using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. We investigated the associations between the HER2 Ile655Val polymorphism and clinical outcomes in women with HER2-negative breast cancer and with HER2-positive breast cancer who received trastuzumab or who did not.

Results: At a median follow-up of 44 months, HER2 Ile655Val polymorphism was not significantly associated with survival either in the entire study population of 4167 patients or in 2976 HER2-negative breast cancer patients. Among 816 HER2-positive patients who received adjuvant chemotherapy and/or endocrine therapy without trastuzumab treatment, patients with the Val/Ile or the Val/Val genotype had a significantly worse disease-free survival (DFS) and distant DFS (DDFS) than those with the Ile/Ile genotype (DFS, adjusted hazard ratio [HR] 1.5; 95% confidence interval [CI] 1.0-2.3; P = 0.037; DDFS, adjusted HR 1.9; 95% CI 1.2-2.9 P = 0.005). In contrast, among 212 HER2-positive patients who received chemotherapy in combination with trastuzumab treatment, patients with the Val/Ile or the Val/Val genotype had a significantly better DFS and DDFS than those with the Ile/Ile genotype (5-year DFS, 100% versus 83%; P = 0.008; 5-year DDFS, 100% versus 89%; P = 0.031).

Conclusions: HER2 Ile655Val polymorphism affects the function of HER2 gene only restricted in HER2-positive breast cancers. HER2-positive breast cancer patients with the Val variant have an aggressive phenotype, but are sensitive to trastuzumab treatment.

Keywords: HER2 gene; breast cancer; polymorphism; response; trastuzumab.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Antibodies, Monoclonal, Humanized / therapeutic use*
  • Antineoplastic Agents / therapeutic use*
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / pathology
  • Drug Resistance, Neoplasm / genetics*
  • Female
  • Genes, erbB-2 / genetics*
  • Humans
  • In Situ Hybridization, Fluorescence
  • Kaplan-Meier Estimate
  • Middle Aged
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length
  • Polymorphism, Single Nucleotide*
  • Proportional Hazards Models
  • Receptor, ErbB-2 / genetics
  • Trastuzumab

Substances

  • Antibodies, Monoclonal, Humanized
  • Antineoplastic Agents
  • ERBB2 protein, human
  • Receptor, ErbB-2
  • Trastuzumab