Non-amplification genetic alterations of HER2 gene in non-small cell lung carcinoma

Prevalence of highly actionable mutations among Indian patients with advanced non-small cell lung cancer: A systematic review and meta-analysis

BACKGROUND

Non-small cell lung cancer (NSCLC) remains a leading cause of cancer-related mortality in India. To clarify rates of actionable mutations, and thereby identify opportunities to improve the delivery of best available care for a large volume of patients, a comprehensive review of available data is warranted.

METHODS

Studies that reported prevalence of any actionable gene variant among adult Indian patients with advanced NSCLC were selected from three databases (PubMed, EMBASE, and Cochrane Library). Ranges in actionable variant prevalence were reported. Meta-analysis of proportions was completed among studies specifically evaluating mutational prevalence within ALK or EGFR. Sensitivity analyses were undertaken among populations sharing high heterogeneity.

RESULTS

Twenty-six studies were selected. Ranges in actionable mutational prevalence among NSCLC patients were as follows: ALK: 4.1-21.4%, BRAF: 1.5-3.5%, EGFR: 11.9-51.8%, HER2: 0-1.5%, KRAS: 4.5-6.4%, NTRK: 0-.7%, and ROS-1: 3.5-4.1%. Following sensitivity analysis, pooled ALK mutational prevalence rates were 8.3% (95% CIs: 6.6-10.4%) and 4.01% (95% CIs: 2.3-7.0) for adenocarcinoma and NSCLC patients, respectively. Pooled EGFR mutational prevalence rates were 28.7% (95% CIs: 23.5-34.6%) and 24.2% (95% CIs: 19.9-29.1%) for adenocarcinoma and NSCLC patients, respectively.

CONCLUSIONS

Nearly 40% of Indian patients with advanced adenocarcinoma and 30% with NSCLC share an actionable mutation in ALK or EGFR. Approximately one-half of adenocarcinoma patients have an actionable variant. Efforts should be directed toward efficiently identifying candidates for targeted agents and delivering such treatments.

Molecular and clinicopathological characteristics of ERBB2 gene fusions in 32,131 Chinese patients with solid tumors

ERBB2 amplification is one of the most important and mature targets for HER2-targeted drug therapy. Somatic mutations of ERBB2 in the tyrosine kinase domain have been studied extensively, and play a role in response to anti-HER2 therapy among different cancer types. However, ERBB2 fusion has not been got attention and its relevance to HER2-targeted therapy is unclear. We comprehensively characterized ERBB2 fusions from next-generation sequencing (NGS) data between May 2018 and October 2021 in 32,131 various solid tumors. Among the tumors, 0.28% harbored ERBB2 fusions, which occurred more commonly in gastroesophageal junction cancer (3.12%; 3/96), breast cancer (1.89%; 8/422), urothelial carcinoma (1.72%; 1/58), and gastric cancer (1.60%; 23/1,437). Our population presented with a median age of 65 years (range 28 to 88 years), a high proportion of men (55 men vs 34 women; 61.80%). Among the patients with ERBB2 fusions, TP53 (82%), APC (18%), and CDK4 (15%) were the top3 co-mutant genes. What’s more, most patients with ERBB2 fusion also had ERBB2 amplification (75.28%; 67/89), which was similar to the data in the TCGA database (88.00%; 44/50). Furthermore, TCGA database shows that patients with ERBB2 fusions in pan-cancer had a worse prognosis than those without ERBB2 fusions, as well as in breast cancer. Besides, ERBB2 amplification combined with ERBB2 fusion had worse prognosis than those with only ERBB2 amplification. ERBB2 fusion may interfere the effect of anti-HER2-targeted antibody drugs and influence the prognosis of patients with ERBB2 amplification. Prospective clinical trials are warranted to confirm the results in the future.

Robust home brew fragment sizing assay for detection of MET exon 14 skipping mutation in non-small cell lung cancer patients in resource constrained community hospitals

BACKGROUND

A mutation/deletion involving donor or acceptor sites for exon 14 results in splicing out of exon 14 of the mesenchymal epithelial transition (MET) gene and is known as "MET exon 14 skipping" (ΔMET14). The two recent approvals with substantial objective responses and improved progression-free survival to MET inhibitors namely capmatinib and tepotinib necessitate the identification of this alteration upfront. We herein describe our experience of ΔMET14 detection by an mRNA-based assay using polymerase chain reaction followed by fragment sizing.

METHODS

This is a home brew assay which was developed with the concept that the transcripts from true ΔMET14 will be shorter by ~140 bases than their wild type counterparts. The cases which were called MET exon 14 skipping positive on next-generation sequencing (NGS) were subjected to this assay, along with 13 healthy controls in order to establish the validity for true negatives.

RESULTS

Thirteen cases of ΔMET14 mutation were detected on NGS using RNA-based sequencing. Considering NGS as a gold standard, the sizing assay using both gel and capillary electrophoresis that showed 100% specificity for both with concordance rates of 84.6% and 88.2% with NGS, respectively, were obtained.

CONCLUSIONS

Owing to the cost-effective nature and easy to use procedures, this assay will prove beneficial for small- and medium-sized laboratories where skilled technical personnel and NGS platforms are unavailable.

What Is New in Biomarker Testing at Diagnosis of Advanced Non-Squamous Non-Small Cell Lung Carcinoma? Implications for Cytology and Liquid Biopsy

The discovery and clinical validation of biomarkers predictive of the response of non-squamous non-small-cell lung carcinomas (NS-NSCLC) to therapeutic strategies continue to provide new data. The evaluation of novel treatments is based on molecular analyses aimed at determining their efficacy. These tests are increasing in number, but the tissue specimens are smaller and smaller and/or can have few tumor cells. Indeed, in addition to tissue samples, complementary cytological and/or blood samples can also give access to these biomarkers. To date, it is recommended and necessary to look for the status of five genomic molecular biomarkers (EGFR, ALK, ROS1, BRAFV600, NTRK) and of a protein biomarker (PD-L1). However, the short- and more or less long-term emergence of new targeted treatments of genomic alterations on RET and MET, but also on others’ genomic alteration, notably on KRAS, HER2, NRG1, SMARCA4, and NUT, have made cellular and blood samples essential for molecular testing. The aim of this review is to present the interest in using cytological and/or liquid biopsies as complementary biological material, or as an alternative to tissue specimens, for detection at diagnosis of new predictive biomarkers of NS-NSCLC.