The findings of a recent study suggest that in postmenopausal women with early-stage breast cancer who were given tamoxifen for 5 years, focal ESR1 amplification was a significant predictor of long-term outcome in early breast cancer. The result of this study was published in an official journal of the American Association of Cancer Research, Clinical Cancer Research.
Gene amplification refers to an increase in the number of copies of a particular gene, in this case the ESR1 gene. The ESR1 gene or estrogen receptor alpha gene (ESR1) encodes an estrogen receptor and ligand-activated transcription factor. Mutation in the ESR1 gene are associated with resistance to endocrine therapy.
The current study included 394 patients who were randomly assigned into the tamoxifen-only arm and who received the adjuvant endocrine therapy. As part of the analysis, formalin-fixed, paraffin-embedded tumor tissue was studied. Assessments such as the Allred score, FISH analysis were used to arrive at the results.
As per the results obtained from the study, it was seen that focal ESR1 amplifications were detected in 187 tumor specimens. After a median follow-up of 10 years, it was noted that breast-cancer specific survival was more in women with intratumoral focal ESR1 amplification as compared with women without it.
Source: Singer CF; ABCSG, Holst F, Steurer S, Burandt EC, Lax SF, Jakesz R, Rudas M, Stöger H, Greil R; ABCSG, Sauter G, Filipits M; ABCSG, Simon R, Gnant M; ABCSG. Estrogen Receptor Alpha Gene Amplification Is an Independent Predictor of Long-Term Outcome in Postmenopausal Patients with Endocrine-Responsive Early Breast Cancer. Clin Cancer Res. 2022 Sep 15;28(18):4112-4120. doi: 10.1158/1078-0432.CCR-21-4328. PMID: 35920686.
