Phase I/II study of prevention of Colorectal Cancer CRC with Allopurinol in High-Risk Subjects

Primary objectives: The primary endpoint of the study is to estimate the activity of allopurinol compared with placebo on the change in cell proliferation by assessment of Ki-67
Primary endpoints: The primary endpoint of the study is to estimate the activity of allopurinol compared with placebo on the change in cell proliferation by assessment of Ki-67, a biomarker of cell proliferation, in CRC tissue at baseline tumor or polyp biopsy and after 4 weeks of allopurinol treatment surgical resection specimen .