The purpose of this study is to assess the feasibility of selecting personalized therapies for colon cancer patients who have failed standard treatments, using a new methodology based on the determination of a profile of chemosensitivity by comprehensive genetic expression analysis from tumor samples.

It is a prospective, randomized study in patients with metastatic colorectal carcinoma progressing after two lines of prior therapy. Patients will be randomized (1:1) to receive chemotherapy as determined by its oncologist or treatment according to chemosensitivity profile obtained. For obtaining the profile a histological tumor sample and a sample of venous blood in a tube with heparin standard are necessary . This latter sample will be processed to isolate circulating tumor cells by cell adhesion with matrix coated glass spheres. The RNA from these circulating tumor cells as well as from tumor cells of tumor biopsies from the same patients will be extracted by a standard procedure for extracting RNA for genetic expression analysis. Based on the analysis performed on tumor biopsy is generated a ranked list of potentially more effective treatments in every case

Inclusion Criteria:

• Histological examination showed of metastatic colon carcinoma.
• Patients more than 18 years.
• Measurable disease according to RECIST 1.1 criteriso
• Life expectancymore than 3 months according to the criteria of the investigator.
• Goodoverall condition determined by the ECOG scale (score 0-1)
• Candidate for systemic treatment based on the profile of sensibility to drugs determined by genetic analysis of the tumor sample. Patients should have received at least two lines of standard treatment, including therapies antiEGFR in cases of tumors with Kras oncogene B-Raf and native (non-mutated).
• Availability of tumor tissue or potential for tumor biopsy correlation allowing the RNA expression profile with that obtained from the peripheral blood CTCs.
• Adequate hematologic function: ANCmore than 1.5 x 103 / L, platelet count absolute more than 100 x 109 / L, normal values of INR and PTT.
• Adequate liver function: total serum bilirubin no more than 2 mg / dL, ALT and AST no more than 3 times the upper limit established by the laboratory (LSR) or no more than 5 LSR in patients with liver metastases.
• Adequate renal function: serum creatinine no more than 1.5 LSR or calculated creatinine clearance 60 ml / min (Crock).

Exclusion Criteria:

• The patient has received systemic cancer treatment within two weeks prior to extraction of the blood sample.
• Patient has received therapeutic radioisotopes such as strontium 89 within 4 weeks before blood extraction.
• Patient has had major surgery or percutaneous procedures such as placement of central venous catheter within 2 weeks prior to the blood draw.
• Patient has a history as bone marrow transplantation and / or stem cell transplantation.
• Patient has any of the following concomitant diseases or current conditions:

chronic active liver disease of any origin, and / or cirrhosis with Child-Pugh score B or C.

Uncontrolled active infection. carries the human immunodeficiency virus (HIV). Any other significant disease that in the opinion of the investigator, substantially increase the risk associated with patient participation in this study.

documented symptomatic brain metastases, progression or requiring corticosteroids or associated to a leptomeningeal involvement.

Patients with uncontrolled systemic diseases. Patients with Hypertension or Diabetes Mellitus is countable if at the time of inclusion deemed medically controlled.

Patients with inability for oral drug delivery, either by preventing gastrointestinal administration situation or severe impairment of intestinal absorption

• Any medical or psychiatric condition that, in the opinion of the investigator, may limit the patient's ability to understand and fulfill all requirements under its partcipación in the study.
• Pregnant or lactating women