Subsequent analysis of the four DS-GPA factors for lung cancer (age, KPS, number of extracranial and brain metastases), genetic mutation status (EGFR, ALK, K-RAS), smoking index, sex, race, histopathological grade, and total number of brain metastases revealed EGFR and ALK to be new prognostic factors in patients with lung adenocarcinoma [8]. Here, EGFR is linked to lung adenocarcinoma.