HER2 insertion YVMA mutant lung cancer: Long natural history and response to afatinib.

Human epidermal growth factor 2 (HER2, ERBB2) mutations in lung cancers are oncogenic drivers that respond to HER2 targeted therapies. Little is known about the sensitivity of subtypes of HER2 mutant lung cancers to targeted agents. We present a patient with HER2 mutant lung cancer with a 12 base pair insertion YVMA (p.A775_G776insYVMA), who had a long natural history and durable partial response to afatinib. We demonstrate that afatinib has activity in patients with HER2 mutant lung cancers with exon 20 YVMA insertions, the most common variant.