Mechanisms of Fate Evolution of Colorectal Adenocarcinoma Metastasis

Stage Ⅰ is a cross-sectional study to record selected information and biospecimen of more than 200 colorectal cancer cases( at least 160 stage Ⅲ cases,40 stage Ⅳ（synchronous metastasis）).Stage Ⅱ is a nested case-control study. 200 eligible cases enrolled in phaseⅠwill be followed up for 5 years to record recurrence, metastasis and to collect biospecimen . Each case with the study outcome will be matched with the corresponding control according to the proportion of 1:1 according to age, sex and other conditions, and further analysis will be made.