Molecular landscape of ERBB2/HER2 gene amplification among patients with gynecologic malignancies; clinical implications and future directions

Objective: Investigate the prevalence of ERBB2/HER2 gene amplification among patients with gynecologic malignancies.

Methods: The American Association of Cancer Research (AACR) Genomics Evidence of Neoplasia Information Exchange (GENIE) (version 13.1) database was accessed and patients with endometrial, ovarian, and cervical cancer were identified. Patients with available data on the presence of copy-number gene alterations were selected for further analysis. Incidence of ERBB2 amplification following stratification by tumor site and histology was evaluated. Data from the OncoKB database, as provided by cBioPortal, was utilized to determine presence of pathogenic genomic alterations.

Results: A total of 6961 patients who met the inclusion criteria were identified: 49.1% with ovarian cancer, 45.2% with endometrial cancer and 5.7% with cervical cancer respectively. Overall incidence of ERBB2 amplification was 3.8%. Highest incidence of ERBB2 amplification was observed among patients with mucinous ovarian (14.4%), uterine serous (13.2%), uterine clear cell (9.4%), and uterine carcinosarcoma (7.9%). ERBB2 amplification was rare among patients with TP53 wild-type endometrioid endometrial cancer (0.4%). High incidence of mutations in genes of the PI3K pathway was observed among patients with ERBB2 amplified tumors.

Conclusion: ERBB2 amplification is frequently encountered among patients with uterine serous carcinoma, and mucinous ovarian carcinoma. In addition, a high incidence was also observed among those with uterine clear cell carcinoma, and uterine carcinosarcoma. For patients with endometrioid endometrial carcinoma, incidence of ERBB2 amplification is low, especially in the absence of TP53 mutations.