Inclusion Criteria:

- Histologically confirmed diagnosis of colorectal cancer.

- ECOG Performance Status 0-2 (Appendix A).

- Patient is a candidate for oxaliplatin based therapy either in the adjuvant or in the
metastatic setting.

- Consent to donate 4 tubes of PBMC of 7 ml of blood each.

- Willing to consider additional post therapy tumor biopsy if applicable (refusal to
consent is not an exclusion criteria).

- Adequate organ function as defined as:

- Neutrophil count > 1500/μl

- Platelets > 75,000/ μl

- Hemoglobin > 8 g/dl

- Bilirubin < 2.0 X upper limit of normal

- Creatinine < 2 mg% or calculated clearance > 40 ml/mt

- The patient must have signed a consent form approved by the Albert Einstein College
of Medicine Cancer Center CCI and Montefiore Medical Center IRB

Exclusion Criteria:

- No other significant underlying medical condition that will, in the opinion of the
principal investigator or designees, make administration of oxaliplatin unusually
hazardous, such as significant hepatic, bone marrow and/or cardiac disease, requiring
active medical treatment.

- Pregnant women or women of child bearing potential not practicing birth control or
sexually active males unwilling to practice contraception during the study.

- Patients undergoing major surgical procedures (they will be delayed enrollment until
complete recovery from their surgery - 4 wk for major or 2 wk from minor surgery).

- Patients with grade 2 neuropathy will not be eligible for the study.

- The patient must not have received chemotherapy within 4 weeks of beginning
oxaliplatin treatment. At least 6 weeks must elapse if prior therapy included
mitomycin C or nitrosoureas. At least 2 weeks must have elapsed since the end of
prior palliative radiation therapy.