Novel NLRC4-ALK and EML4-ALK double fusion mutations in a lung adenocarcinoma patient: A case report

Concomitant double-fusion of PLEKHA7-ALK and INPP5D-ALK reveals favorable alectinib sensitivity in lung adenocarcinoma: a case report and literature review

Anaplastic lymphoma kinase (ALK) gene fusion is a classic driver mutation in non-small cell lung cancer (NSCLC); however, ALK double-fusion variants in NSCLC have rarely been reported. In this study, we reported a case with extremely uncommon ALK double-fusion variants. A 32-year-old female diagnosed with lung adenocarcinoma, who had developed multiple intrapulmonary and brain metastases, experienced worsening of her condition despite undergoing prior chemotherapy. Subsequent testing using next-generation sequencing (NGS) detected the presence of PLEKHA7-ALK and INPP5D-ALK double-fusion. The prescription of alectinib revealed potent efficacy and resulted in an increase in the survival rate. This case presented two uncommon and concomitant ALK fusion partners in NSCLC; more importantly, the INPP5D-ALK subtype has not been reported, therefore this study broadens the spectrum of ALK double-fusion variants and provides insight into the use of ALK inhibitors for the treatment of NSCLC in patients with double ALK fusions.

Coexistence of a novel SETD2-ALK, EML4-ALK double-fusion in an advanced lung adenocarcinoma patient after alectinib resistant and response to immunotherapy combined with chemotherapy: a case report

The single echinoderm microtubule-associated protein-like 4 (EML4) gene and anaplastic lymphoma kinase (ALK) gene fusion is the most common variant of ALK rearrangements in non-small cell lung cancer (NSCLC). Herein, we firstly report that coexistence of a novel histone methyltransferase (SETD2)-ALK, EML4-ALK double-fusion is sensitive to alectinib as first-line therapy, and response to immunotherapy combined with chemotherapy after resistant. The patient responded to alectinib as a first-line therapy and achieved progression-free survival (PFS) for 26 months. After resistance, liquid biopsy showed that the reason of drug resistance was the disappearance of SETD2-ALK and EML4-ALK fusion variants. In addition, chemotherapy combined with immunotherapy subsequently achieved a survival benefit of more than 25 months. Therefore, alectinib may be a viable therapeutic option for NSCLC patients with double ALK fusion and immunotherapy combined with chemotherapy may be a viable therapeutic option when double ALK fusion loss may be the mechanism of alectinib resistance.

Therapeutic Advances of Rare ALK Fusions in Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases and is the leading cause of cancer-related death. Despite advances in chemotherapy and immunotherapy, the prognosis for advanced patients remains poor. The discovery of oncogenic driver mutations, such as anaplastic lymphoma kinase (ALK) mutations, means that a subset of patients has opportunities for targeted therapy. With the improvement of genetic testing coverage, more and more ALK fusion subtypes and ALK partners have been discovered, and more than 90 rare ALK fusion subtypes have been found in NSCLC. However, unlike the common fusion, echinoderm microtubule-associated protein-like 4 (EML4)-ALK, some rare ALK fusions such as striatin (STRN)-ALK and huntingtin interacting protein 1 (HIP1)-ALK, etc., the large-scale clinical data related to its efficacy are still immature. The clinical application of ALK-tyrosine kinase inhibitors (ALK-TKIs) mainly depends on the positivity of the ALK gene, regardless of the molecular characteristics of the fusion partner. Recent clinical studies in the ALK-positive NSCLC population have demonstrated differences in progression-free survival (PFS) among patients based on different ALK fusion subtypes. This article will introduce the biological characteristics of ALK fusion kinase and common detection methods of ALK fusion and focus on summarizing the differential responses of several rare ALK fusions to ALK-TKIs, and propose corresponding treatment strategies, so as to better guide the application of ALK-TKIs in rare ALK fusion population.

Chimeric RNAs Discovered by RNA Sequencing and Their Roles in Cancer and Rare Genetic Diseases

Chimeric RNAs are transcripts that are generated by gene fusion and intergenic splicing events, thus comprising nucleotide sequences from different parental genes. In the past, Northern blot analysis and RT-PCR were used to detect chimeric RNAs. However, they are low-throughput and can be time-consuming, labor-intensive, and cost-prohibitive. With the development of RNA-seq and transcriptome analyses over the past decade, the number of chimeric RNAs in cancer as well as in rare inherited diseases has dramatically increased. Chimeric RNAs may be potential diagnostic biomarkers when they are specifically expressed in cancerous cells and/or tissues. Some chimeric RNAs can also play a role in cell proliferation and cancer development, acting as tools for cancer prognosis, and revealing new insights into the cell origin of tumors. Due to their abilities to characterize a whole transcriptome with a high sequencing depth and intergenically identify spliced chimeric RNAs produced with the absence of chromosomal rearrangement, RNA sequencing has not only enhanced our ability to diagnose genetic diseases, but also provided us with a deeper understanding of these diseases. Here, we reviewed the mechanisms of chimeric RNA formation and the utility of RNA sequencing for discovering chimeric RNAs in several types of cancer and rare inherited diseases. We also discussed the diagnostic, prognostic, and therapeutic values of chimeric RNAs.

Concomitant novel ALK-SSH2, EML4-ALK and ARID2-ALK, EML4-ALK double-fusion variants and confer sensitivity to crizotinib in two lung adenocarcinoma patients, respectively

Introduction

Anaplastic lymphoma kinase (ALK) gene rearrangements, have been identified in approximately 2-7% of patients with lung adenocarcinoma (LUAD). However, co-occurrence of double ALK fusions in one patient was rare. Herein, we reported two Chinese female LUAD patients with confirmed double ALK fusion variants by next generation sequencing.

Case presentation

Case 1, a 38-year-old female was diagnosed as peripheral LUAD in left upper lobe with synchronous multiple intrapulmonary metastases (pT2N0M1b, stage IVa). And case 2, a 58-year-old female had left lower lobe primary LUAD and synchronous multiple lung metastases (pT4N2M1b, stage IVa). In both patients, tumor cells displayed strong expression of ALK protein. Genetic profiling by next generation sequencing showed both patients concurrently harbored two types of ALK rearrangements. Case 1 had an unreported ALK-SSH2/EML4-ALK double fusions, and case 2 had an another novel ARID2-ALK/EML4‐ALK double fusions. Both of these patients responded to ALK inhibitor crizotinib.

Conclusions

Our study reported two novel ALK fusion partners never reported, which expands the knowledge of ALK fusion spectrum and provides insight into therapeutic options for patients with double ALK fusions.

Long-Term Survival After Salvage Thoracic Surgery on a Patient with ALK-Rearranged Metastatic Lung Adenocarcinoma After Progression on Targeted Therapy

Targeted therapy for patients with advanced non-small cell lung cancer (NSCLC) is often challenged by the arising of drug resistance. After progression to targeted therapy, treatment options include continued targeted therapy, definitive local therapy, and the combination of both. While there is evidence that local ablative radiotherapy may prolong the disease control by targeted therapy, little is known regarding the relevance of salvage thoracic surgery in this setting. Herein, we presented a case of stage IV lung adenocarcinoma with concurrent EML4-ALK and TAC1-ALK fusion who had long-term survival after salvage thoracic surgery. The patient underwent a multidisciplinary treatment scheme that consisted of radiotherapy, ALK inhibitor crizotinib, and surgery, with blood-based genomic profiling for monitoring disease progression. Notably, salvage thoracic surgery was performed after progression on the crizotinib therapy and acquired ALK F1174C mutation was identified, which has been shown to be resistant to crizotinib and possibly sensitive to ceritinib. The patient benefited from salvage thoracic surgery with a remarkable progression-free survival of 31 months at last follow-up, and the patient maintained high-performance status throughout the course of management. To the best of our knowledge, this is the first case reporting on the long-term survival outcome from salvage thoracic surgery after crizotinib treatment in an NSCLC patient carrying double ALK fusion.