This research study will assess cruciferous vegetable intake in patients presenting for screening colonoscopy and correlate intake with histone status and histone deacetylace (HDAC) expression in tissue biopsy specimens and peripheral blood mononuclear cells (PBMCs). The investigators will also measure sulforaphane (SFN) metabolites in blood as a biomarker of cruciferous vegetable intake.

Inclusion criteria:

• scheduled for screening colonoscopy
• off NSAID or aspirin therapy in accordance with OHSU endoscopy clinic guidelines
• INR 0.90-1.20
• hemoglobin ≥ 13.5 (men) or 12.0 (women)
• platelets ≥100,000/μL
• Chem screen results within normal limits
• negative (serum or urine) pregnancy test done ≤7 days prior to colonoscopy for women of childbearing potential only
• ASA performance status <2

Exclusion criteria:

• history of colon cancer or adenomatous polyps
• current smoker
• medical history of chronic obstructive pulmonary disease
• current oral steroid therapy
• current therapy with valproate or other pharmacological drugs associated with HDAC inhibition
• use of oral antibiotics within 3 months prior to entry into study
• significant active medical illness which in the opinion of the investigator would preclude collection/interpretation of colon tissue
• diagnosis of hemophilia, van Willebrand's disease or other bleeding disorder
• use of warfarin or other blood thinning agents
• inflammatory bowel disease.

Patients scheduled for screening colonoscopy

Group information (High versus Low Cruciferous Vegetable Intake) will be made available. No IPD will be made available.