On the other hand, preclinical evidence is conflicting on whether Ang1 overexpression by genetic approaches (Ahmad et al, 2001; Hawighorst et al, 2002; Tian et al, 2002; Machein et al, 2004; Holopainen et al, 2009; Hwang et al, 2009; Schulz et al, 2011) has positive or negative effects on tumor growth and metastasis. This evidence concerns the gene ANGPT1 and neoplasm.