The aim of this study is to find some genetic factors in predicting the sensibility of preoperative chemoradiotherapy for locally advanced rectal carcinoma.

For locally advanced rectal carcinoma,preoperative chemoradiotherapy(CRT) achieved similar overall survival and better local control compared with postoperative therapy,so it was considered to be one of the standard therapy of these patients.But,not every one will be cured,the possible reason is the difference gene expression and mutation status among patients.So,we performed this trial to study the relationship between genetic factors and response of preoperative CRT for locally advanced rectal cancer.

Inclusion Criteria:

• Pathologically confirmed rectal adenocarcinoma, preoperative stage II / III (T3-4N0 or T1-4N + M0).
• Distance from the lower bound of tumor to the anal verge is less than 12 cm.
• KPS score not less than 70
• Can be tolerated chemotherapy and radiotherapy.
• No history of radiation therapy to the pelvis.
• Non-allergic history of fluorouracil or platinum-based chemotherapy drugs.
• Full understanding of the study, the ability to complete all of the treatment plan, follow up the conditions and sign the informed consent. -

Exclusion Criteria:

• Other malignancy (past or at the same time), does not include curable non-melanoma skin cancer and cervical carcinoma in situ; does not include resectable primary colon cancer (synchronous or metachronous).
• Pregnant or lactating patients.
• Fertility but did not use contraceptive measures.
• Existing active infection.
• Merge serious complications, can not tolerate the treatment, such as 6 months of myocardial infarction, mental illness, uncontrollable diabetes or uncontrollable hypertension or hypotension.
• Concurrent treatment with other anticancer drugs.
• Can not complete treatment or follow-up