» Articles » PMID: 39695741

ERBB2/HOXB13 Co-amplification with Interstitial Loss of BRCA1 Defines a Unique Subset of Breast Cancers

Overview
Specialty Oncology
Date 2024 Dec 19
PMID 39695741
Authors
Affiliations
Soon will be listed here.
Abstract

Background: The HOXB13/IL17RB gene expression biomarker has been shown to predict response to adjuvant and extended endocrine therapy in patients with early-stage ER+ HER2- breast tumors. HOXB13 gene expression is the primary determinant driving the prognostic and endocrine treatment-predictive performance of the biomarker. Currently, there is limited data on HOXB13 expression in HER2+ and ER- breast cancers. Herein, we studied the expression of HOXB13 in large cohorts of HER2+ and ER- breast cancers.

Methods: We investigated gene expression, genomic copy number, mutational signatures, and clinical outcome data in the TGGA and METABRIC breast cancer cohorts. Genomic-based gene amplification data was validated with tri-colored fluorescence in situ hybridization.

Results: In the TCGA breast cancer cohort, HOXB13 gene expression was significantly higher in HER2+ versus HER2- breast cancers, and its expression was also significantly higher in the ER- versus ER+ breast cancers. HOXB13 is frequently co-gained or co-amplified with ERBB2. Joint copy gains of HOXB13 and ERBB2 occurred with low-level co-gains or high-level co-amplifications (co-amp), the latter of which is associated with an interstitial loss that includes the tumor suppressor BRCA1. ERBB2/HOXB13 co-amp tumors with interstitial BRCA1 loss exhibit a mutational signature associated with APOBEC deaminase activity and copy number signatures associated with chromothripsis and genomic instability. Among ERBB2-amplified tumors of different tissue origins, ERBB2/HOXB13 co-amp with a BRCA1 loss appeared to be enriched in breast cancer compared to other tumor types. Lastly, patients with ERBB2/HOXB13 co-amplified and BRCA1 lost tumors displayed a significantly shorter progression-free survival (PFS) than those with ERBB2-only amplifications. The difference in PFS was restricted to the ER- subset patients and this difference in PFS was not solely driven by HOXB13 gene expression.

Conclusions: HOXB13 is frequently co-gained with ERBB2 at both low-copy number level or as complex high-level amplification with relative BRCA1 loss. ERBB2/HOXB13 amplified, BRCA1-lost tumors are strongly enriched in breast cancer, and patients with such breast tumors experience a shortened PFS.

References
1.
Brechka H, Bhanvadia R, VanOpstall C, Vander Griend D . HOXB13 mutations and binding partners in prostate development and cancer: Function, clinical significance, and future directions. Genes Dis. 2017; 4(2):75-87. PMC: 5548135. DOI: 10.1016/j.gendis.2017.01.003. View

2.
Taylor A, Shih J, Ha G, Gao G, Zhang X, Berger A . Genomic and Functional Approaches to Understanding Cancer Aneuploidy. Cancer Cell. 2018; 33(4):676-689.e3. PMC: 6028190. DOI: 10.1016/j.ccell.2018.03.007. View

3.
Allison K, Hammond M, Dowsett M, McKernin S, Carey L, Fitzgibbons P . Estrogen and Progesterone Receptor Testing in Breast Cancer: ASCO/CAP Guideline Update. J Clin Oncol. 2020; 38(12):1346-1366. DOI: 10.1200/JCO.19.02309. View

4.
Hung Y, Ueda M, Terai Y, Kumagai K, Ueki K, Kanda K . Homeobox gene expression and mutation in cervical carcinoma cells. Cancer Sci. 2003; 94(5):437-41. PMC: 11160166. DOI: 10.1111/j.1349-7006.2003.tb01461.x. View

5.
Lopez R, Garrido E, Vazquez G, Pina P, Perez C, Alvarado I . A subgroup of HOX Abd-B gene is differentially expressed in cervical cancer. Int J Gynecol Cancer. 2006; 16(3):1289-96. DOI: 10.1111/j.1525-1438.2006.00603.x. View