A diagnostic assay for cancer such as lung cancer is disclosed. The assay can also be used to follow patients during treatment and for assessment of disease relapse after treatment. The assay utilizes biomarkers for tumor formation identified in a transgenic mouse model. The assay is used to identify a therapeutic indication for a patient based on the patient's biomarker expression. The biomarker and fragments thereof are also useful for treating cancer, for example lung or colon cancer.
