To investigate the mechanism of enhanced anti-tumor effect of PDMP treatment in combination with RT, animals were sacrificed after 2 and 10 days of treatment (Gong et al., 2009), and tumor tissue was harvested for immunohistochemical analysis, Western blot analysis and flow cytometry for markers, including γ-H2AX, CD31, CD133 and ATM. This evidence concerns the gene PECAM1 and neoplasm.