Prognostic Factors for Patients With Advanced Colorectal Cancer Treated With Cetuximab.

Inclusion criteria * Signed written informed consent for biological analysis (all pts) * Signed written informed consent for enrolment (pts with KRAS wild type) * Male or female aged \> or = 18 years * Diagnosis of histologically confirmed adenocarcinoma of the colon or rectum * KRAS evaluation availability with wild-type result * Metastatic CRC not suitable for curative-intent resection * Availability of tumour samples (or able and willing to provide tumour sample) and blood for biological analysis * Presence of at least one lesion measurable unidimensionally by computed tomography (CT) scan or magnetic resonance imaging (MRI). (index lesion(s) must not lie within an irradiated area) * Eastern cooperative oncology group-performance status (ECOG-PS) \<2 Exclusion criteria * Brain metastasis (known or suspected) * Previous chemotherapy for metastatic CRC (any). Adjuvant therapy is allowed if the chemotherapy treatment free interval is \> 6 months * Surgery (excluding diagnostic biopsy) or irradiation within 4 weeks prior to study entry * Concurrent chronic systemic immune therapy, chemotherapy, or hormone therapy not indicated in the study protocol * Any investigational agent(s) within 4 weeks prior to entry * Previous exposure to HER-axis -pathway targeting therapy * Leucocytes \<3.0 x 109/L and neutrophils \<1.5 x 109/L, platelets \<100 x 109/L, and hemoglobin \<9 g/dL * Bilirubin level either normal or \>1.5 x ULN * ASAT and ALAT \>2.5 x ULN (\>5 x ULN if liver metastasis are present) * Serum creatinine \>1.5 x ULN * Clinically relevant coronary artery disease or a history of a myocardial infarction within the last 12 months * Acute or sub-acute intestinal occlusion or history of inflammatory bowel disease * Pre-existing neuropathy \> grade 1 * Known grade 3 or 4 allergic reaction to any of the components of the treatment * Any concurrent malignancy other than non-melanoma skin cancer, or carcinoma in situ of the cervix. (Pts with a previous malignancy but without evidence of disease for \> or equal 5 years will be allowed to enter the trial) * Pregnancy or lactation * Inadequate contraception (male or female pts) if of childbearing or procreational potential * Known drug abuse/ alcohol abuse * Legal incapacity or limited legal capacity * Medical or psychological condition which in the opinion of the investigator would not permit the patient to complete the study or sign meaningful informed consent