EPHA2 and neoplasm: In contrast, tumor-bearing mice injected with the negative control 64CuMeCOSar-shWTCH2 showed only minor tracer uptake in their tumors, similar to background activity, at any measured time point and a similar lack of tumor uptake was seen for the positive control IgG, 64CUMeCOSar-IgG, which binds to EphA2 (Table 9, Fig 9).