ERBB2 and adenocarcinoma: Regarding the epidemiology of HER2 MUT in lung cancer, small retrospective studies from around the world reported that HER2 mutations are present mostly in adenocarcinoma histology and are more frequent in women, younger patients (median age 60 years old), patients with a low exposure to tobacco (never or light smokers), and in patients of oriental ethnicities, compared to other ethnicities (Table S1) [12,13,14,15,16,17,18,19].