Angiogenic Switch in Patients With Colorectal Cancer

Inclusion Criteria: * Diagnosis of stage IV colorectal adenocarcinoma. * Age ≥ 18 years . * Measurable disease by RECIST criteria. * Life expectancy ≥ 6 months. * Candidate to receive treatment with first-line chemotherapy. * Availability of tumor tissue. Exclusion Criteria: * Patients who have received prior treatment with first-line chemotherapy for metastatic disease. * Patients in whom there is contraindication to the administration of either drug used in the study: capecitabine, irinotecan, oxaliplatin or Bev. * Patients receiving anticoagulant oral treatment. * Patient with diagnosis of other malignancies within 5 years prior to diagnosis except basal cell carcinoma or cervical carcinoma · in situ. · The inclusion of patients with malignant disease diagnosed more than 5 years ago without recurrence in the previous 3 years will be analyzed individually * Patients with bone disease as the only manifestation of the disease.