Biomarkers
Tumor
BLOOD, TUMOR
Blood samples were collected to measure biomarkers including osteopontin, interleukin‐8 (IL‐8) and soluble AXL. Tumor tissue samples were used to assess the presence of EGFR mutations and to analyze other exploratory biomarkers including AXL expression by immunohistochemistry (IHC). IHC staining was performed using a rabbit monoclonal antibody (C89E7) against AXL purchased from Cell Signaling Technology.