Carcinoembryonic antigen cell adhesion molecule 6 predicts breast cancer recurrence following adjuvant tamoxifen

Loaie Maraqa, Michele Cummings, Mark B Peter, Abeer M Shaaban, Kieran Horgan, Andrew M Hanby, Valerie Speirs

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


PURPOSE: Tamoxifen remains therapy of choice for premenopausal estrogen receptor alpha-positive breast cancer. However, resistance and recurrence are serious problems. Our previous work indicated that carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6) was significantly up-regulated in tamoxifen-resistant (TAMr) MCF-7 derivatives. The aim of this study was to determine the functional role of CEACAM6 in endocrine-resistant breast cancer and to retrospectively test whether it was predictive of resistance in a large cohort of breast cancers with long-term follow-up.

EXPERIMENTAL DESIGN: siRNA silencing of CEACAM6 was done in TAMr cells and effects on clonogenicity and endocrine sensitivity were determined. CEACAM6 immunohistochemistry was done on a tissue microarray comprising 108 relapsed primary human breast cancers and 243 tamoxifen-sensitive controls.

RESULTS: siRNA-mediated silencing of CEACAM6 reduced both clonogenicity and anchorage-dependent and anchorage-independent growth of TAMr cells. Importantly, CEACAM6 silencing restored sensitivity of TAMr cells to 4-hydroxytamoxifen and proliferative response to 17beta-estradiol. Immunohistochemistry showed significantly more CEACAM expression in the relapsed group compared with nonrelapsed controls [35 of 108 (33.3%) and 32 of 243 (13.2%), respectively; odds ratio, 3.16 (95% confidence interval, 1.83-5.47); P < 0.0001]. Additionally, we derived an outcome predictor model based on CEACAM expression that restratified patients in the Nottingham prognostic index intermediate-risk group into either higher-risk or lower-risk group.

CONCLUSIONS: Our data support an important role for CEACAM6 in endocrine resistance, which can serve as a powerful predictor of future recurrence.

Original languageEnglish
Pages (from-to)405-11
Number of pages7
JournalClinical Cancer Research
Issue number2
Publication statusPublished - 15 Jan 2008
Externally publishedYes


  • Antigens, CD
  • Antineoplastic Agents, Hormonal
  • Breast
  • Breast Neoplasms
  • Cell Adhesion Molecules
  • Cell Line, Tumor
  • Cell Proliferation
  • Chemotherapy, Adjuvant
  • Drug Resistance, Neoplasm
  • Estradiol
  • Estrogen Antagonists
  • GPI-Linked Proteins
  • Humans
  • Neoplasm Recurrence, Local
  • Prognosis
  • RNA Interference
  • Selective Estrogen Receptor Modulators
  • Tamoxifen
  • Tissue Array Analysis
  • Journal Article
  • Research Support, Non-U.S. Gov't


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