A Novel CAMKMT Exon3-ALK Exon20 Fusion Variant was Identified in a Primary Pulmonary Mucinous Adenocarcinoma

Chemotherapy in combination with pembrolizumab and antiangiogenesis in young patients with advanced primary pulmonary mucinous adenocarcinoma: Two case reports

Primary pulmonary mucinous adenocarcinoma is an unusual histological type of non-small cell lung cancer and has a rare prevalence at a young age. There is no standard first-line therapy for advanced primary pulmonary mucinous adenocarcinoma in children and young adults-this study reports two rare cases of primary pulmonary mucinous adenocarcinoma with wild-type anaplastic lymphoma kinase and epidermal growth factor receptor (EGFR) genes. One is a 13-year-old boy (Case#1), and another is a 27-year-old male (Case#2). Both two cases were treated with antibiotics for suspected pulmonary infection. In our hospital, they were diagnosed with advanced primary pulmonary mucinous adenocarcinoma, the Eastern Cooperative Oncology Group (ECGO) performance status was three scores. We chose pembrolizumab and chemotherapy plus angiogenesis inhibitors for Case#1 and Case#2. The two patients' symptoms improved and presented with a partial response according to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria，the scores of ECOG performance status were two for Case#1 and one for Case#2. This study illustrates a promising outcome for advanced primary pulmonary mucinous adenocarcinoma with immunotherapy and chemotherapy plus angiogenesis inhibitors at a young age.

Potential Unreliability of Uncommon ALK, ROS1, and RET Genomic Breakpoints in Predicting the Efficacy of Targeted Therapy in NSCLC

INTRODUCTION

Variable genomic breakpoints have been identified through the application of target-capture DNA next-generation sequencing (NGS) for ALK, ROS1, and RET fusion detection in NSCLC. We investigated whether ALK, ROS1, and RET genomic breakpoint location can predict matched targeted therapy efficacy.

METHODS

NSCLCs were analyzed by DNA NGS, target-specific RNA NGS, whole-transcriptome sequencing, and immunohistochemistry.

RESULTS

In total, 3787 NSCLC samples were analyzed. DNA NGS detected ALK, ROS1, and RET fusions in 241, 59, and 76 cases, respectively. These fusions were divided into canonical (single EML4-ALK, CD74/EZR/TPM3/SDC4-ROS1, and KIF5B/CCDC6-RET fusions), noncanonical (single non-EML4-ALK, non-CD74/EZR/TPM3/SDC4-ROS1, and non-KIF5B/CCDC6-RET fusions), and primary/reciprocal (both primary and reciprocal rearrangements were detected) subtypes on the basis of genomic breakpoint position, and noncanonical and primary/reciprocal subtypes were defined as uncommon fusions. Further RNA sequencing and immunohistochemistry revealed that six of 47 (12.8%) uncommon fusions were actually nonproductive rearrangements that generated no aberrant transcripts or proteins. Moreover, genomic breakpoints of canonical ALK and RET, but not ROS1, fusions always predicted breakpoints at the transcript level, whereas 85.4% (35 of 41) of uncommon fusions actually produced canonical fusion transcripts. Patients with uncommon ALK fusion (n = 31) who received first-line crizotinib exhibited shorter median progression-free survival than those with canonical ALK fusion (n = 53, 8.4 mo versus 12.0 mo, p = 0.004). However, no difference in progression-free survival was observed when only ALK RNA or protein-positive cases were analyzed (p = 0.185).

CONCLUSIONS

Uncommon ALK, ROS1, and RET genomic breakpoint is an unreliable predictor of matched targeted therapy efficacy. Functional validation by RNA or protein assay may add value for the accurate detection and interpretation of rare fusions.

Catalog of 5' Fusion Partners in ALK-positive NSCLC Circa 2020

Since the discovery of anaplastic lymphoma kinase fusion-positive (ALK+) NSCLC in 2007, the methods to detect ALK+ NSCLC have evolved and expanded from fluorescence in situ hybridization and immunohistochemistry to next-generation DNA sequencing, targeted RNA sequencing, and whole transcriptome sequencing. As such, the deep sequencing methods have resulted in the expansion of distinct fusion partners identified in ALK+ NSCLC to 90 (one variant PLEKHM2-ALK is found in small cell lung cancer but included in this catalog) by the end of January 2020; about 65 of them (since 2018) and most of the recent novel fusion partners were reported from China. Thirty-four of the distinct fusion partners are located on the short arm of chromosome 2; 28 of these 34 fusion partners are located on 2p21-25, in which ALK is located on 2p23.2-p23.1. Many of these new ALK+ NSCLC fusion variants have responded to ALK tyrosine kinase inhibitors (TKIs). Several of these novel ALK fusion variants were identified as being resistant to EGFR TKIs or as dual 3'ALK fusions. In addition, at least 28 intergenic ALK rearrangements have also been reported, with three of them reported as responding to crizotinib. This review aims to serve as a central source of reference of fusion partners in ALK+ NSCLC for clinicians and scientists. We aim to update and improve the list going forward.