The results of our study can be summarized as follows: i) NRG1 rearrangements are firstly well described in a cohort of Caucasian lung adenocarcinoma patients and represent a feature of pulmonary IMA; ii) prevalence of NRG1 fusions in Caucasian patients is similar to that reported in Asian population; iii) pErbB3 immunostaining is a strong predictor of NRG1 fusions; iv) NRG1 rearrangements are not mutually exclusive to KRAS mutations in IMAs also in Caucasian patients. Here, KRAS is linked to lung adenocarcinoma.