GSTM1 and adenoma: Independent of the location, the amount of bleeding of invasive cancers (mean=86.6 ng Hb per ml) was higher than that of high-risk adenomas (mean=71.9 ng Hb per ml) that was in turn higher than those of small adenomas (mean=52.7 ng Hb per ml) or normal colon (mean=54.3 ng Hb per ml).