Response to Anti-HER2-Based Treatment in a Patient with Bladder Adenocarcinoma Harboring HER2 Amplification and S310F Mutation Discovered by Next-Generation Sequencing: A Case Report

Characterizing the Genomic Landscape of the Micropapillary Subtype of Urothelial Carcinoma of the Bladder Harboring Activating Extracellular Mutations of ERBB2

The micropapillary subtype of urothelial carcinoma (MPUC) of the bladder is a very aggressive histological variant of urothelial bladder cancer (UBC). A high frequency of MPUC contains activating mutations in the extracellular domain (ECD) of ERBB2. We sought to further characterize ERBB2 ECD-mutated MPUC to identify additional genomic alterations that have been associated with tumor progression and therapeutic response. In total, 5,485 cases of archived formalin-fixed, paraffin-embedded UBC underwent comprehensive genomic profiling to identify ERBB2 ECD-mutated MPUC and evaluate the frequencies of genomic co-alterations. We identified 219 cases of UBC with ERBB2 ECD mutations (74% S310F and 26% S310Y), of which 63 (28.8%) were MPUC. Genomic analysis revealed that TERT, TP53, and ARID1A were the most common co-altered genes in ERBB2-mutant MPUC (82.5%, 58.7%, and 39.7%, respectively) and did not differ from ERBB2-mutant non-MPUC (86.5%, 51.9%, and 35.3%). The main differences between ERBB2 ECD-mutated MPUC compared with non-MPUC were KMT2D, RB1, and MTAP alterations. KMT2D and RB1 are tumor-suppressor genes. KMT2D frequency was significantly decreased in ERBB2 ECD-mutated MPUC (6.3%) in contrast to non-MPUC (27.6%; P < .001). RB1 mutations were more frequent in ERBB2 ECD-mutated MPUC (33.3%) than in non-MPUC (17.3%; P = .012). Finally, MTAP loss, an emerging biomarker for new synthetic lethality-based anticancer drugs, was less frequent in ERBB2 ECD-mutated MPUC (11.1%) than in non-MPUC (26.9%; P = .018). Characterizing the genomic landscape of MPUC may not only improve our fundamental knowledge about this aggressive morphological variant of UBC but also has the potential to identify possible prognostic and predictive biomarkers that may drive tumor progression and dictate treatment response to therapeutic approaches.

Interaction between HER2 and ATM predicts poor survival in bladder cancer patients

Human Epidermal Growth Factor Receptor 2 (HER2) overexpression is considered one of the interesting prognostic biomarkers in bladder cancer. However, the mechanism of bladder cancer development in relation to HER2 status remains to be elucidated. In this study, we investigated HER2-Ataxia telangiectasia mutated (ATM) kinase interaction and their impact on patient survival and cancer aggressiveness. Using the Cancer Genome Atlas (TCGA) cohorts, we demonstrated that ATM expression (protein/mRNA) is increased in HER2 deficient compared with proficient HER2 patients. This finding was then validated using the Gene Expression Omnibus database (GEO). Correlation analysis (using low expression vs high expression as a discriminator) revealed a significant association of ATM low and HER2 high status with several clinicopathological variables such as high tumour grade, late disease stage and tumour shape. Kaplan-Meier survival analysis indicated that ATM low and HER2 high is a powerful prognosticator of both overall survival (OS) and disease-free survival (DFS). Furthermore, using bioinformatics and protein/protein interaction analyses, we identified 66 putative overlapping proteins with direct link between HER2 and ATM most of which are functionally involved in transcription regulation, apoptotic process and cell proliferation. Interestingly, the results showed that these proteins are strongly linked with PI3K-Akt pathway, p53 pathway and microRNAs in cancer. Altogether, our data pinpoint an important biological role of the interconnection between HER2 and ATM. The latter appear to be an independent prognostic biomarker and may serve as targets to develop novel combination therapies to improve the outcome of patients with bladder cancer.

Efficacy of targeted therapy in patients with HER2-positive non-small cell lung cancer: A systematic review and meta-analysis

Anti-human epidermal growth factor receptor 2 (HER2) therapy is an effective treatment for HER2-positive gastric and breast malignancies. However, the efficacy of HER2-targeted therapy in non-small cell lung cancer (NSCLC) patients with HER2 alterations remains controversial. We searched studies on HER2-targeted therapy in NSCLC patients that reported objective response rate (ORR), disease control rate (DCR) and progressionfree survival (PFS) published from database inception to 30 May 2021. A total of 32 trials involving 958 patients were included. The ORRs of HER2-TKIs targeted therapy, humanised monoclonal antibody, trastuzumab-based treatment and antibody-drug conjugate (ADC) (T-DM1) were 22% (95% CI 11-31), 23% (95% CI 20-65), 26% (95% CI 14-39) and 16% (95% CI _6-37), while that of ADC (DS-8201) was 60% (95% CI 35-85). The DCRs of these groups were 59% (95% CI 49-69), 39% (95% CI _9-88), 63% (95% CI 37-89), 31% (95% CI 4-58) and 87% (95% CI 62-112), respectively. In the subgroup analysis, numerically higher ORRs and DCRs were observed in the poziotinib (38%; 75%) and pyrotinib (35%; 83%) groups. The median PFSs of these groups were 5.51 months, 3.09 months, 4.61 months, 2.65 months and 12.04 months, respectively. HER2-targeted therapy can be considered an acceptable treatment strategy for NSCLC patients with HER2 alterations. In particular, ADC (DS-8201), pyrotinib and poziotinib demonstrated promising anti-tumour activity in HER2-positive NSCLC.

Targeting HER2 genomic alterations in non-small cell lung cancer

Oncogenic mutations and amplifications in the erythroblastic oncogene B (ERBB2), or human epidermal growth factor receptor 2 (HER2), have emerged as distinct oncogenic drivers and drug targets in non-small cell lung cancer (NSCLC). Each genomic alteration occurs in 2-4% of NSCLC by next generation sequencing and is associated with constitutive HER2 activation. The most common HER2 mutations in NSCLC are exon 20 mutation A775_G776insYVMA mutation in the kinase domain and S310F mutation in the extracellular domain. Unlike in breast and gastric cancer, HER2 protein overexpression in NSCLC is not validated to be a biomarker predictive of clinical response to HER2-targeted agents. High HER2 protein overexpression by immunohistochemistry (3+) only occurs in 2-4% of NSCLC. Until now HER2-targeted agents (such as afatinib and ado-trastuzumab emtansine) only demonstrate modest clinical activity in patients with HER2-mutant NSCLC. Retrospective studies show concern for inferior clinical benefit of immune checkpoint inhibitors in HER2-mutated NSCLC. Therefore, platinum-based chemotherapy with or without an anti-angiogenesis inhibitor remains the first line standard treatment for this patient population. In May 2020 trastuzumab deruxtecan (T-DXd) received the U.S. Food and Drug Administration breakthrough therapy designation for HER2-mutant metastatic NSCLC, and was added as an option for HER2-mutant NSCLC to the NCCN guidelines V1.2021. A global phase III study of pyrotinib compared to docetaxel as a second line therapy for advanced NSCLC harboring HER2 exon 20 mutations was just opened for enrollment in September 2020. In this review, we highlight the current knowledge and perspectives on targeting-HER2 genomic alterations in NSCLC.