RET and lung cancer: RET fusions have been identified in 5–10% of papillary thyroid cancers and 1–2% of lung cancers and involve distinct fusion partners, including KIF5B in lung adenocarcinoma and CCDC6 in thyroid and lung cancer (Grieco et al., 1990; Kohno et al., 2012; Takeuchi et al., 2012; Lipson et al., 2012).