A Novel MYH9-RET Fusion Occurrence and EGFR T790M Loss as an Acquired Resistance Mechanism to Osimertinib in a Patient with Lung Adenocarcinoma: A Case Report

Exploring the nexus between MYH9 and tumors: novel insights and new therapeutic opportunities

The myosin heavy chain 9 (MYH9) gene, located on human chromosome 22, encodes non-muscle myosin heavy chain IIA (NM IIA). This protein is essential to various cellular events, such as generating intracellular chemomechanical force and facilitating the movement of the actin cytoskeleton. Mutations associated with thrombocytopenia in autosomal dominant diseases first highlighted the significance of the MYH9 gene. In recent years, numerous studies have demonstrated the pivotal roles of MYH9 in various cancers. However, its effects on cancer are intricate and not fully comprehended. Furthermore, the elevated expression of MYH9 in certain malignancies suggests its potential as a target for tumor therapy. Nonetheless, there is a paucity of literature summarizing MYH9's role in tumors and the therapeutic strategies centered on it, necessitating a systematic analysis. This paper comprehensively reviews and analyzes the pertinent literature in this domain, elucidating the fundamental structural characteristics, biological functions, and the nexus between MYH9 and tumors. The mechanisms through which MYH9 contributes to tumor development and its multifaceted roles in the tumorigenic process are also explored. Additionally, we discuss the relationship between MYH9-related diseases (MYH9-RD) and tumors and also summarize tumor therapeutic approaches targeting MYH9. The potential clinical applications of studying the MYH9 gene include improving early diagnosis, clinical staging, and prognosis of tumors. This paper is anticipated to provide novel insights for tumor therapy.

Liquid biopsy for the management of NSCLC patients under osimertinib treatment

Therapeutic management of NSCLC patients is quite challenging as they are mainly diagnosed at a late stage of disease, and they present a high heterogeneous molecular profile. Osimertinib changed the paradigm shift in treatment of EGFR mutant NSCLC patients achieving significantly better clinical outcomes. To date, osimertinib is successfully administered not only as first- or second-line treatment, but also as adjuvant treatment while its efficacy is currently investigated during neoadjuvant treatment or in stage III, unresectable EGFR mutant NSCLC patients. However, resistance to osimertinib may occur due to clonal evolution, under the pressure of the targeted therapy. The utilization of liquid biopsy as a minimally invasive tool provides insight into molecular heterogeneity of tumor clonal evolution and potent resistance mechanisms which may help to develop more suitable therapeutic approaches. Longitudinal monitoring of NSCLC patients through ctDNA or CTC analysis could reveal valuable information about clinical outcomes during osimertinib treatment. Therefore, several guidelines suggest that liquid biopsy in addition to tissue biopsy should be considered as a standard of care in the advanced NSCLC setting. This practice could significantly increase the number of NSCLC patients that will eventually benefit from targeted therapies, such as EGFR TKIs.

Fusion Genes Landscape of Lung Cancer Patients From Inner Mongolia, China

Lung cancer is the leading cause of cancer-related deaths globally. Gene fusion, a key driver of tumorigenesis, has led to the identification of numerous driver gene fusions for lung cancer diagnosis and treatment. However, previous studies focused on Western populations, leaving the possibility of unrecognized lung cancer-associated gene fusions specific to Inner Mongolia due to its unique genetic background and dietary habits. To address this, we conducted DNA sequencing analysis on tumor and adjacent nontumor tissues from 1200 individuals with lung cancer in Inner Mongolia. Our analysis established a comprehensive fusion gene landscape specific to lung cancer in Inner Mongolia, shedding light on potential region-specific molecular mechanisms underlying the disease. Compared to Western cohorts, we observed a higher occurrence of ALK and RET fusions in Inner Mongolian patients. Additionally, we discovered eight novel fusion genes in three patients: SLC34A2-EPHB1, CCT6P3-GSTP1, BARHL2-APC, HRAS-MELK, FAM134B-ERBB2, ABCB1-GIPC1, GPR98-ALK, and FAM134B-SALL1. These previously unreported fusion genes suggest potential regional specificity. Furthermore, we characterized the fusion genes' structures based on breakpoints and described their impact on major functional gene domains. Importantly, the identified novel fusion genes exhibited significant clinical and pathological relevance. Notably, patients with SLC34A2-EPHB1, CCT6P3-GSTP1, and BARHL2-APC fusions showed sensitivity to the combination of chemotherapy and immunotherapy. Patients with HRAS-MELK, FAM134B-ERBB2, and ABCB1-GIPC1 fusions showed sensitivity to chemotherapy. In summary, our study provides novel insights into the frequency, distribution, and characteristics of specific fusion genes, offering valuable guidance for the development of effective clinical treatments, particularly in Inner Mongolia.

RET rearrangement as a mechanism of resistance to ALK-TKI in non-small cell lung cancer patient with EML4-ALK fusion: A case report

Patients with non-small cell lung cancer (NSCLC) and anaplastic lymphoma kinase (ALK) mutations have previously derived substantial benefits from ALK tyrosine kinase inhibitors (ALK-TKIs). However, resistance may develop in some patients. We present a case of co-mutation with anaplastic lymphoma kinase (ALK) and rearranged during transfection (RET)-rearranged NSCLC, representing a novel resistance mechanism to ALK-TKIs, in which the patient exhibited a favorable response to combination therapy with ensartinib and pralsetinib. Notably, the patient survived 12 months without experiencing adverse events, a rare occurrence in ALK-rearranged lung adenocarcinoma cases. This case provides further evidence for the existence of RET rearrangements in ALK-positive lung cancer and their potential treatment response to a combination of ALK inhibitors and pralsetinib. This case underscores that a dual-target therapy involving ALK inhibitors, specifically ensartinib and pralsetinib, could be a viable approach in cases of RET-rearranged lung cancer with concurrent targetable ALK mutations. We propose the consideration of this dual-target approach, specifically employing ensartinib and pralsetinib, in managing RET-rearranged lung cancer coexisting with targetable ALK mutations. Given the potential efficacy of these treatments, it is imperative to proactively conduct molecular profiling tests in NSCLC patients upon the emergence of resistance.

Acquired resistance mechanisms to osimertinib: The constant battle

Lung cancer is the leading cause of cancer-related mortality worldwide. Detectable driver mutations have now changed the course of lung cancer treatment with the emergence of targeted therapy as a novel strategy that widely improved lung cancer prognosis, especially in metastatic patients. Osimertinib (AZD9291) is an irreversible third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) used to treat stage IV EGFR-mutated non-small-cell lung cancer. It was initially designed to target both EGFR-activating mutations and the EGFR T790M mutation as well, which is the most common resistance mechanism to first- and second-generation EGFR-TKIs. Following the FLAURA trial, osimertinib is now widely used in the first-line setting. However, resistance to osimertinib inevitably develops, with numerous mechanisms leading to its resistance, classified into two main categories: EGFR-dependent and EGFR-independent mechanisms. While EGFR-dependent mechanisms consist mainly of the C797S EGFR mutation, EGFR-independent mechanisms include bypass pathways, oncogenic fusions, and phenotypic transformation, among others. This review summarizes the molecular resistance mechanisms to osimertinib, with the aim of identifying novel therapeutic approaches to overcome osimertinib resistance and improve patient outcome.

Case Report: A novel intergenic MIR4299/MIR8070-RET fusion with RET amplification and clinical response to pralsetinib in a lung adenocarcinoma patient

The identification of receptor-tyrosine kinase gene (RET) fusions in lung cancer has become crucial owing to actionable events that predict responsiveness to tyrosine kinase inhibitors (TKIs). However, RET fusions with distinct partner genes respond differently to TKIs. In this case, a 60-year-old man was diagnosed with advanced lung adenocarcinoma. A novel RET-MIR4299/MIR8070 fusion and RET amplification were identified using next-generation sequencing (NGS). The patient was then administered with pralsetinib. After 3 weeks of therapy, the patient had a partial response. At the time of reporting, the patient was on continuous pralsetinib. These findings broaden the range of RET fusion types and provide the basis for the hypothesis that RET intergenic fusion and amplification respond to pralsetinib treatment in lung adenocarcinoma.

Acquired Mechanisms of Resistance to Osimertinib-The Next Challenge

Simple Summary

Osimertinib has revolutionized the treatment of EGFR-mutated tumors. Its current applications include the first-line setting, second-line setting, as well as the adjuvant setting. Although it represents a milestone in the context of targeted therapy, inevitably all tumors develop an acquired resistance, some mechanisms involve EGFR, others do so through alternative pathways leading to a bypass in osimertinib inhibition. It is key to understand these acquired mechanisms of resistance, both in the clinical setting, as well as in preclinical models, in order to develop and contribute to the identification of possible therapeutic strategies to overcome this acquired resistance.

Abstract

EGFR-mutated tumors represent a significant percentage of non-small cell lung cancer. Despite the increasing use of osimertinib, a treatment that has demonstrated an outstanding clinical benefit with a tolerable toxicity profile, EGFR tumors eventually acquire mechanisms of resistance. In the last years, multiple mechanisms of resistance have been identified; however, after progressing on osimertinib, treatment options remain bleak. In this review, we cover the most frequent alterations and potential therapeutic strategies to overcome them.

Emerging a Novel VOPP1-EGFR Fusion Coexistent With T790M as an Acquired Resistance Mechanism to Prior Icotinib and Sensitive to Osimertinib in a Patient With EGFR L858R Lung Adenocarcinoma: A Case Report

Background

Epidermal growth factor receptor (EGFR) fusions are rare genomic events in non-small-cell lung cancer (NSCLC). Clinical support and evidence to guide management are absent for NSCLC patients harboring EGFR fusion.

Case Presentation

In this case report, we describe a 69-year-old female who received right lobectomy and was diagnosed with pathological stage IIIA lung adenocarcinoma harboring EGFR L858R. Twenty months later he had recurrent disease in the liver, lung, and bone, and was treated with icotinib. A novel vesicular overexpressed in cancer pro-survival protein 1 (VOPP1)-EGFR fusion gene coexistent with T790M were identified by next-generation sequencing using pericardial effusion and blood samples after icotinib treatment, which led to progression after icotinib six months and suggested a potential resistance mechanism. Subsequently, the patient was switched to osimertinib treatment, which resulted in a progression-free survival interval of more than 11 months.

Conclusions

The present results suggested that acquired VOPP1-EGFR fusion gene with T790M potentially serve an additional resistance mechanism to first-generation EGFR tyrosine kinase inhibitors in EGFR-mutated NSCLC. And the present case increases the evidence supporting use of osimertinib for treatment of NSCLC patients harboring EGFR fusion.

Management of Oligometastasis and Oligoprogression in Patients with Epidermal Growth Factor Receptor Mutation-Positive NSCLC in the Era of Third-Generation Tyrosine Kinase Inhibitors

This review covers the importance of local consolidative therapy (LCT) in patients with epidermal growth factor receptor (EGFR) mutation-positive with oligometastatic and oligoprogressive non-small-cell lung cancer (NSCLC). With the advent of third-generation EGFR tyrosine kinase inhibitors, a more updated review is necessary. We review the efficacy of LCT, pathophysiological background, and treatment modalities other than radiotherapy. In addition, we also discussed when and how LCT should be applied to patients with oligometastatic and oligoprogressive NSCLC.