In the subgroup of patients with NSCLC with brain metastases, the high expression of AXL (AXLHigh) was significantly associated with GAS6 expression (P < 0.001), but not with tumor differentiation, gender, age, smoking history, pathology, T stage, N stage, CEA, and LDH (all P > 0.05) (Table 5). This evidence concerns the gene AXL and neoplasm.