PROBLEM TO BE SOLVED: To clarify a molecule mechanism of a ligand-independent activation of EphA2 in a cancer cell to make EphA2 a more useful target for a cancer treatment, and to provide an examination method of cancer or the like using the mechanism.SOLUTION: An examination method of cancer or the like includes a step of measuring an amount of EphA2 protein fragments having molecular weight of 30 kDa to 80 kDa in a sample originating in a subject.SELECTED DRAWING: None