In roughly 1% of non small cell lung cancers (NSCLC), particularly in adenocarcinoma, chromosomal inversions cause the fusion of the RET-encoded TK domain to different exons of KIF5B (kinesin family member 5B) gene or, less commonly, to CCDC6, NCOA4 or TRIMM33 [4–8]. The gene discussed is RET; the disease is non-small cell lung carcinoma.