To define the role of the tumor microenvironment (TME) in mediating response to TKI therapy in ALK positive lung cancer, we have used an orthotopic immunocompetent model whereby murine EML4-ALK fusion-positive lung cancer cells are directly implanted into the lungs of syngeneic C57BL/6 mice20–22. The gene discussed is EML4; the disease is neoplasm.