Co-overexpression of GEP100 and AMAP1 proteins correlates with rapid local recurrence after breast conservative therapy

PLoS One. 2013 Oct 7;8(10):e76791. doi: 10.1371/journal.pone.0076791. eCollection 2013.

Abstract

A major problem of current cancer research and therapy is prediction of tumor recurrence after initial treatment, rather than the simple biological characterization of the malignancy and proliferative properties of tumors. Breast conservation therapy (BCT) is a well-approved, standard treatment for patients with early stages of breast cancer, which consists of lumpectomy and whole-breast irradiation. In spite of extensive studies, only 'age' and 'Ki-67 positivity' have been identified to be well correlated with local recurrence after BCT. An Arf6 pathway, activated by GEP100 under receptor tyrosine kinases (RTKs) and employs AMAP1 as its effector, is crucial for invasion and metastasis of some breast cancer cells. This pathway activates β1 integrins and perturbs E-cadherin-based adhesions, hence appears to be integral for epithelial-mesenchymal transdifferentiation (EMT). We here show that expression of the Arf6 pathway components statistically correlates with rapid local recurrence after BCT. We retrospectively analyzed four hundred seventy-nine patients who received BCT in Hokkaido University Hospital, and found 20 patients had local recurrence. We then analyzed pathological samples of patients who experienced local recurrence by use of Kaplan-Meier analysis, Stepwise regression analysis and the t-test, coupled with immunostaining, and found that co-overexpression of GEP100 and AMAP1 correlates with rapidity of the local recurrence. Their margin-status, node-positivity, and estrogen receptor (ER)- or progesterone receptor (PgR)-positivity did not correlated with the rapidity. This study is the first to show that expression of a certain set of proteins correlates with the rapidity of local recurrence. Our results are useful not only for prediction, but highlight the possibility of developing novel strategies to block local recurrence. We also discuss why mRNAs encoding these proteins have not been identified to correlate with local recurrence by previous conventional gene expression profiling analyses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / biosynthesis*
  • Adult
  • Aged
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology
  • Breast Neoplasms / therapy*
  • Chemoradiotherapy
  • Combined Modality Therapy
  • Female
  • Guanine Nucleotide Exchange Factors / biosynthesis*
  • Humans
  • Immunohistochemistry
  • Kaplan-Meier Estimate
  • Mastectomy, Segmental / methods
  • Middle Aged
  • Neoplasm Recurrence, Local*
  • Regression Analysis
  • Retrospective Studies
  • Time Factors
  • Treatment Outcome

Substances

  • ASAP1 protein, human
  • Adaptor Proteins, Signal Transducing
  • Guanine Nucleotide Exchange Factors
  • IQSEC1 protein, human

Grants and funding

This work was supported by Grants-in-aid from the Ministry of Education, Science, Sports and Culture of Japan, Mitsubishi Foundation for Natural Sciences, Takeda Science Foundation to H. Sabe, The Funding Program for World-Leading Innovative R & D on Science and Technology (FIRST program http://www.jsps.go.jp/j-first/gaiyou.html) to H. Shirato, and Grant-in-Aid for Young Scientists (B) from the Ministry of Education, Culture, Sports, Science and Technology of the Japanese Government http://www.jsps.go.jp/j-grantsinaid/) (No.24791259) to R. Kinoshita. J.-M. Nam was supported by a grant from the Matching Program for Innovations in Future Drug Discovery and Medical Care from the Ministry of Education, Culture, Sports, Science, and Technology of Japan (MEXT). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manusclipt