Indeed, Z1 staining was significantly increased in CD31-high cells in Eml4-Alk lung tissue sections relative to CD31-high cells in healthy lungs, as well as relative to CD31-low cells in both Eml4-Alk and healthy tissue (P < 0.0001; Fig. 5b), suggesting specific activity associated with the Eml4-Alk tumor endothelium. Here, PECAM1 is linked to neoplasm.