Determination of RAS Mutation Status in Liquid Biopsies in Subjects With RAS Wild-type.PERSEIDA Study

Inclusion criteria: * Subjects who give their informed consent in writing * Subjects with metastatic colorectal cancer, measurable by RECIST, who start first-line treatment * Male and female subjects, at least 18 years of age and of any ethnicity * Subjects with a histologically-confirmed diagnosis of colorectal carcinoma with metastatic disease and wild-type RAS. Exclusion criteria: * Pregnant or breastfeeding women * Subjects who have previously received monoclonal antibodies against EGFR (cetuximab or panitumumab), small-molecule EGFR inhibitors (such as erlotinib) or other biological cancer treatments * History of another solid or haematological tumour in the previous 5 years, except a history of basal cell carcinoma of the skin or pre-invasive cervical cancer * Subjects who are participating or have participated in a clinical trial in the 30 days prior to inclusion.