We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
EGFR is a Therapeutic Target in Hormone Receptor-Positive Breast Cancer.
- Authors
Yisun Jeong; Soo Youn Bae; Daeun You; Seung Pil Jung; Hee Jun Choi; Isaac Kim; Se Kyung Lee; Jonghan Yu; Seok Won Kim; Jeong Eon Lee; Sangmin Kim; Seok Jin Nam
- Abstract
Background/Aims: Despite effective therapeutic strategies for treating hormone receptor-positive (HR+) breast cancer, resistance to endocrine therapy that is either de novo or acquired still occurs. We investigated epidermal growth factor receptor (EGFR) as a therapeutic target for overcoming endocrine resistance in HR+ breast cancer models. Methods: Using clinical data from 2,166 patients who had HR+ breast tumors and received tamoxifen, we analyzed survival rates. Levels of mRNA and protein expression were analyzed by real-time PCR and western blotting, respectively. Cell viability was analyzed by MTT assays and anchorage-independent growth by soft agar colony-formation assays. Efficacy of tamoxifen and/or gefitinib was analyzed using orthotopic xenograft mouse models. Results: EGFR expression was significantly associated with more advanced stage and higher grade. EGFR expression was different in luminal A-like (Lum A, 1.3%) versus luminal B-like (Lum B, 11.4%) subtypes. On multivariate analyses for survival Lum B subtype EGFR+ tumors showed a hazard ratio (HR) of 5.22 (95% CI, 1.29–21.15, P = 0.020) for overall survival (OS) and HR of 2.91 (95% CI, 1.35–6.28, P = 0.006) for disease-free survival (DFS). Levels of EGFR inversely correlated with ER-α expression. Basal ER-α level was completely blocked by TGFA or EGF treatment. With TGFA pretreatment, ER+ breast cancer cells were resistant to 4-hydroxytamoxifen (4-OHT). Conversely, downregulation of ER-α by TGFA was reversed by gefitinib with recovered sensitivity to 4-OHT. Tumorigenicity of EGFR and ER+ breast cancer cells were significantly decreased by combined tamoxifen and gefitinib. Conclusion: Aberrant EGFR expression was associated with poor prognosis in ER+ breast cancers, especially the Lum B subtype. Loss of ER by EGFR activation induced tamoxifen resistance. Therefore, EGFR could be a therapeutic target for overcoming recurrence of ER+ breast cancer with high EGFR expression.
- Subjects
HORMONE receptor positive breast cancer; HORMONE therapy; BREAST cancer treatment; EPIDERMAL growth factor receptors; MESSENGER RNA
- Publication
Cellular Physiology & Biochemistry (Cell Physiol Biochem Press GmbH & Co. KG), 2019, Vol 53, Issue 5, p805
- ISSN
1015-8987
- Publication type
Article
- DOI
10.33594/000000174