In the OAK study, patients baseline characteristics include more EGFR KRAS mutation positive and ALK fusion positive patients, those patients who receive previous treatment with tyrosine kinase inhibitor are more likely to experience pneumonitis and lung inflammation (Choi et al., 2013; Awad and Nott, 2016; Chiang et al., 2016; Yoo et al., 2016). Here, KRAS is linked to pneumonitis.