PRevention Using EPA Against coloREctal Cancer

Inclusion Criteria: Participants must meet the following criteria on screening examination to be eligible to participate in the study: * Underwent screening or surveillance colonoscopy with removal of at least one adenoma; * Age 18-80 years. * This study will only include adult participants because colorectal carcinogenesis in children is more likely to be related to a cancer predisposition syndrome with distinct biological mechanisms compared with sporadic colorectal cancer in adults. Patients over age 80 will not be enrolled since the benefits and risks of AMR101 over the age of 80 have not yet been well-characterized. * ECOG performance status ≤2 (Karnofsky ≥60%, see Appendix A) * The effects of AMR101 on the developing human fetus are unknown. For this reason, women of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while she is participating in this study, she should inform her treating physician immediately. * Subjects must be able and willing to follow study procedures and instructions. * Ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: Participants who exhibit any of the following conditions at screening will not be eligible for admission into the study * Currently using or have used any fish oil supplement at any dose more than once per week within the last month * Regularly consuming more than three servings of fish per week. * History of allergic reactions attributed to fish or compounds of similar chemical or biologic composition to omega-3 fatty acid. * Diagnosis of inflammatory bowel disease, liver or kidney disease, bleeding diathesis * Any prior diagnosis of gastrointestinal cancer (including esophageal, small intestine, colon, pancreatic), or any diagnosis of other cancers (with the exception of nonmelanoma skin) in which there has been any active treatment within the last three years. * Known diagnosis of Familial Adenomatous Polyposis (FAP) or Hereditary Non-Polyposis Colorectal Cancer (HNPCC, Lynch Syndrome). * Any adenoma that was not completely removed during previous colonoscopy. * Known bleeding tendency/condition (e.g. von Willebrand disease) or history of peptic ulcer or gastrointestinal bleed, endoscopic complications, or contraindication to colonoscopy. * Current use of anticoagulant therapies, including Heparin, Warfarin, Dalteparin sodium,Bivalirudin, Argatroban, Lepirudin, Heparin Sodium, Heparin/Dextrose, and an unwillingness or inability to discontinue anticoagulants. * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. * Inability or unwillingness to abstain from non-protocol use of fish oil supplements or to provide blood or stool samples or colon biopsies during the study. * Participants who are receiving any other investigational agents. * Inability or unwillingness to swallow pills. * Pregnant or breastfeeding. The effects of AMR101 on the developing human fetus are unknown. For this reason,women of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while she is participating in this study, she should inform her treating physician immediately. Similarly, lactating women are excluded from this study because there is an unknown but potential risk of adverse events in nursing infants secondary to treatment of the mother with AMR101. Consequently, breastfeeding should be discontinued if the mother is enrolled on the study. * Known positive test for human immunodeficiency virus (HIV), hepatitis C virus, or acute or chronic hepatitis B infection. Participants with these infections are ineligible because they are at increased risk of significant complications in the perioperative period, and because fresh tissue from patients with these infections cannot be harvested for research purposes, per institutional policy. Appropriate studies will be undertaken in participants receiving combination antiretroviral therapy when indicated.