ALK and metastatic malignant neoplasm in the lymph nodes: ALK rearranged lung adenocarcinomas were less frequently located in the right upper lobe (0.0% vs. 25.6%, p = 0.013) compared to ALK wildtype tumors and more commonly showed ipsilateral mediastinal or subcarinal lymph node metastasis (N2) compared to EGFR mutated and ALK wildtype tumors (52.9% vs. 22.2%, p = 0.016 and 52.9% vs. 24.8%, p = 0.022) (Tables 3 and 4) (Fig 1).