Molecular profile or tumors had been important pieces of information in cancer care. There are numerous evidences describing the correlation between genetic information and targeted therapy. For example, testing for EGFR L858R or exon 19 deletion, the most critical mutation in non-small lung cancer (NSCLC), have been established as a routine practice in NSCLC. The test result indicates whether to administer EGFR tyrosine kinase inhibitor (TKI). However, there are limited clinical evidences with less common or rare mutations. The authors report two cases with the less common ERBB2 transmembrane domain (TMD) mutation, and they were treated with afatinib and confirmed clinical benefits. Patient 1 had familial lung cancer with germline ERBB2 G660D mutation, was treated with afatinib, and have shown partial response. Patient 2 had ampullary adenocarcinoma with ERBB2 G660D and S310F co-mutations, were treated with afatinib, and have shown obvious clinical improvement of stenotic hydronephrosis. Other cases with the less common ERBB2 mutation had been reported in The Cancer Genome Atlas (TCGA) and the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) database. These cases suggest that establishing a database on clinical genomic information and therapeutic outcome, especially in the patients with less common mutations, is important in precision medicine.
Source: Yamamoto H, Toyooka S, Ninomiya T, et al. Oncologist. 2018;23(2):150-154