The identification of a small but significant subset of patients still targetable with anti-HER2 inhibitors when affected by triple negative breast carcinoma

J Cancer Res Clin Oncol. 2013 Sep;139(9):1563-8. doi: 10.1007/s00432-013-1479-0. Epub 2013 Jul 28.

Abstract

Purpose: Triple (ER-, PR-, HER2-) negative breast carcinoma lack targeted therapies, making this group of tumors difficult to treat. By definition, the lack of HER2 expression means a case scoring 0 or 1+ after immunophenotypical analysis and makes the patients avoiding therapeutical chances with anti-HER2 inhibitors. We sought to recruit from a group of triple negative breast carcinoma, patients eligible for effective personalized targeted therapy with anti-HER therapies on the basis of their HER2 gene status.

Methods: 135 patients diagnosed with IHC triple negative breast carcinoma were studied. Whole tissue sections were used for in situ hybridization analysis.

Results: 8/100 (8 %) of ductal-type triple negative breast carcinoma presented Her-2/neu gene amplification versus 2/35 (5.7 %) non-ductal triple negative breast carcinoma. Three cases showed a ratio 2.5. One case showed Her-2/neu heterogeneous gene amplification, ratio 2.3. The other six showed from 7 to 8 absolute Her-2/neu gene copy number. Two cases staged pT1c, and eight cases staged pT2. Eight cases graded G3 and two cases G2.

Conclusion: (1) Eight percentage of ductal and 5.7 % non-ductal-type triple negative breast carcinoma present Her-2/neu gene amplification, (2) the standard diagnostic flowchart "do not FISH in 0-1+ (HER2-) breast carcinoma" should be replaced by "do FISH in triple (ER-, PR-, HER2-) negative breast carcinoma," to avoid loss of therapeutical chances in a cohort of such a patients, (3) we demonstrated the identification of a small but significant subset of patients targetable with anti-HER2 inhibitors, giving patients affected by (ex)triple negative breast carcinoma new personalized therapeutical chances.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Monoclonal, Humanized / therapeutic use*
  • Antineoplastic Agents / therapeutic use
  • Apocrine Glands / metabolism
  • Apocrine Glands / pathology
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Carcinoma, Ductal, Breast / drug therapy*
  • Carcinoma, Ductal, Breast / metabolism
  • Carcinoma, Ductal, Breast / pathology
  • Carcinoma, Squamous Cell / drug therapy*
  • Carcinoma, Squamous Cell / metabolism
  • Carcinoma, Squamous Cell / pathology
  • Cohort Studies
  • Female
  • Follow-Up Studies
  • Gene Amplification
  • Humans
  • Immunoenzyme Techniques
  • In Situ Hybridization, Fluorescence
  • Middle Aged
  • Neoplasm Grading
  • Neoplasm Staging
  • Prognosis
  • Receptor, ErbB-2 / antagonists & inhibitors*
  • Receptor, ErbB-2 / genetics
  • Receptor, ErbB-2 / metabolism
  • Receptors, Estrogen / metabolism*
  • Receptors, Progesterone / metabolism*
  • Trastuzumab

Substances

  • Antibodies, Monoclonal, Humanized
  • Antineoplastic Agents
  • Receptors, Estrogen
  • Receptors, Progesterone
  • Receptor, ErbB-2
  • Trastuzumab