On the basis of the above findings, it is not unexpected that some investigators have proposed prophylactic cranial irradiation (PCI) for EGFR positive NSCLC patients.47 None of the PCI studies in NSCLC has so far demonstrated an improved OS, therefore this is not a routine practice as in small-cell lung cancer, although studies have been able to show a reduced incidence and delayed appearance of BM by 50%. The gene discussed is EGFR; the disease is small cell lung carcinoma.