Breast Cancer Research and Treatment

, Volume 120, Issue 2, pp 409–418

Phosphatidylinositol-3-kinase and AKT1 mutations occur early in breast carcinoma

  • Jennifer Dunlap
  • Claudia Le
  • Arielle Shukla
  • Janice Patterson
  • Ajia Presnell
  • Michael C. Heinrich
  • Christopher L. Corless
  • Megan L. Troxell
Preclinical study

DOI: 10.1007/s10549-009-0406-1

Cite this article as:
Dunlap, J., Le, C., Shukla, A. et al. Breast Cancer Res Treat (2010) 120: 409. doi:10.1007/s10549-009-0406-1

Abstract

Mutationally activated protein kinases are appealing therapeutic targets in breast carcinoma. Mutations in phosphatidylinositol-3-kinase (PI3KCA) have been described in 8–40% of invasive breast carcinomas, and AKT1 mutations have been characterized in 1–8% of breast carcinomas. However, there is little data on these mutations in breast precursor lesions. To further delineate the molecular evolution of breast tumorigenesis, samples of invasive breast carcinoma with an accompanying in situ component were macro dissected from formalin-fixed paraffin embedded tissue and screened for mutations in PIK3CA exons 7, 9, 20, and AKT1 exon 2. Laser capture micro dissection (LCM) was performed on mutation-positive carcinomas to directly compare the genotypes of separated invasive and in situ tumor cells. Among 81 cases of invasive carcinoma, there were eight mutations in PIK3CA exon 20 (7 H1047R, 1 H1047L) and four mutations in exon 9 (2 E545K, 1 E542K, 1 E545G), totaling 12/81 (14.8%). In 11 cases examined, paired LCM in situ tumor showed the identical PIK3CA mutation in invasive and in situ carcinoma. Likewise, 3 of 78 (3.8%) invasive carcinomas showed an AKT1 E17K mutation, and this mutation was identified in matching in situ carcinoma in both informative cases. Mutational status did not correlate with clinical parameters including hormone receptor status, grade, and lymph node status. The complete concordance of PIK3CA and AKT1 mutations in matched samples of invasive and in situ tumor indicates that these mutations occur early in breast cancer development and has implications with regard to therapeutics targeted to the PI3 kinase pathway.

Keywords

Phosphatidylinositol-3-kinase (PIK3CA)AKT1Breast carcinomaCarcinoma in situLaser capture microdissection

Copyright information

© Springer Science+Business Media, LLC. 2009

Authors and Affiliations

  • Jennifer Dunlap
    • 1
  • Claudia Le
    • 2
  • Arielle Shukla
    • 2
  • Janice Patterson
    • 2
  • Ajia Presnell
    • 2
  • Michael C. Heinrich
    • 2
    • 3
    • 4
  • Christopher L. Corless
    • 1
    • 2
  • Megan L. Troxell
    • 1
  1. 1.Department of PathologyOregon Health & Science UniversityPortlandUSA
  2. 2.OHSU Knight Cancer InstitutePortlandUSA
  3. 3.Portland Veterans Affairs Medical CenterPortlandUSA
  4. 4.Department of Medicine, Division of Hematology and Medical OncologyOregon Health & Science UniversityPortlandUSA