<i>BRAF</i> in Lung Cancers: Analysis of Patient Cases Reveals Recurrent <i>BRAF</i> Mutations, Fusions, Kinase Duplications, and Concurrent Alterations.

Sheikine, Yuri; Pavlick, Dean; Klempner, Samuel J; Trabucco, Sally E; Chung, Jon H; Rosenzweig, Mark; Wang, Kai; Velcheti, Vamsidhar et al. · JCO Precis Oncol · 2018

case_series · Level IV

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Abstract

Dabrafenib and trametinib are approved for the management of advanced non-small-cell lung cancers (NSCLCs) that harbor <i>BRAF</i> V600E mutations. Small series and pan-cancer analyses have identified non-V600 alterations as therapeutic targets. We sought to examine a large genomic data set to comprehensively characterize non-V600 B<i>RAF</i> alterations in lung cancer. A total of 23,396 patients with lung cancer provided data to assay with comprehensive genomic profiling. Data were reviewed for predicted pathogenic <i>BRAF</i> base substitutions, short insertions and deletions, copy number changes, and rearrangements. Adenocarcinomas represented 65% of the occurrences; NSCLC not otherwise specified (NOS), 15%; squamous cell carcinoma, 12%; and small-cell lung carcinoma, 5%. <i>BRAF</i> was altered in 4.5% (1,048 of 23,396) of all tumors; 37.4% (n = 397) were <i>BRAF</i> V600E, 38% were <i>BRAF</i> non-V600E activating mutations, and 18% were <i>BRAF</i> inactivating. Rearrangements were observed at a frequency of 4.3% and consisted of N-terminal deletions (NTDs; 0.75%), kinase domain duplications (KDDs; 0.75%), and <i>BRAF</i> fusions (2.8%). The fusions involved three recurrent fusion partners: <i>ARMC10</i>, <i>DOCK4,</i> and <i>TRIM24</i>. <i>BRAF</i> V600E was associated with co-occurrence of <i>SETD2</i> alterations, but other <i>BRAF</i> alterations were not and were instead associated with <i>CDKN2A</i>, <i>TP53</i>, and <i>STK11</i> alterations (<i>P</i> < .05). Potential mechanisms of acquired resistance to <i>BRAF</i> V600E inhibition are demonstrated. This series characterized the frequent occurrence (4.4%) of <i>BRAF</i> alterations in lung cancers. Recurrent <i>BRAF</i> alterations in NSCLC adenocarcinoma are comparable to the frequency of other NSCLC oncogenic drivers, such as <i>ALK</i>, and exceed that of <i>ROS1</i> or <i>RET</i>. This work supports a broad profiling approach in lung cancers and suggests that non-V600E BR<i>AF</i> alterations represent a subgroup of lung cancers in which targeted therapy should be considered.