Liver Cancer Prevention Trial in Patients With Chronic Hep C Infection

Inclusion Criteria:

* Chronic hepatitis C infection diagnosed by presence of hepatitis C ribonucleic acid (RNA) in serum by test of hepatitis C virus (HCV) RNA
* No significant alcohol use (7 or fewer drinks per week) for the past 12 months
* Serum AFP (at screening) between 15 and 100 ng/mL (15 ng/mL =\< AFP =\< 100 ng/mL) as measured by the Bayer Advai Centaur chemiluminescence system OR Serum AFP between 10 and 100 ng/mL (10 ng/mL =\< AFP =\<100 ng/mL) as measured by Diagnostic Products Corporation Immulite assay system OR AFP between 12 and 100 ng/mL (12 ng/mL =\< AFP =\< 100 ng/mL) as measured by Ortho ECiQ assay system
* Evidence of advanced liver disease based on one or more of the following:
* Platelet count less than 150,000/mm\^3
* Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio \> 0.75
* Liver biopsy demonstrating bridging fibrosis or cirrhosis
* No treatment with interferon (recombinant interferon alfa), peginterferon (PEG-interferon alfa-2b), or ribavirin for at least 4 months, and not anticipated to start specific treatment for hepatitis C during the study (30 weeks)
* Ultrasound (or adequate computed tomography \[CT\] or magnetic resonance imaging \[MRI\]) examination of the liver within 6 months prior to randomization revealing no masses in the liver suggestive of hepatocellular carcinoma
* Willing to refrain from consuming over-the-counter SAMe and vitamin pills containing B-vitamins while participating in this study (30 weeks)
* Eastern Cooperative Oncology Group (ECOG) performance status 0-2
* Leukocytes \> 1,000/ mm\^3
* Women of child-bearing potential and men 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 participating in this study, she should inform her treating physician immediately
* Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

* Liver disease other than from hepatitis C (e.g., hepatitis B, hemochromatosis, fat in more than 33% of hepatocytes, if liver biopsy has been performed., etc.); subjects with a past history of alcohol use can be enrolled into the study provided they have consumed less than 7 drinks/week for the past 12 months
* Evidence of mass in liver by radiologic examination that is suggestive of hepatocellular carcinoma within 6 months prior to randomization
* Model for End-Stage Liver Disease (MELD) score greater than 15 within 60 days prior to enrollment
* Ascites which is clinically detectable
* Use of SAMe during 4 months prior to randomization
* Hospitalization within the past 5 years for mania or for bipolar disease
* Concurrent use of monoamine oxidase inhibitors (MAO) or other drugs that increase the concentration of serotonin
* Participants may not be receiving any other investigational agents
* History of allergic reactions attributed to compounds of similar chemical or biologic composition to SAMe
* 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
* Children are excluded from this study but will be eligible for future pediatric trials, if applicable
* Pregnant women are excluded from this study; serum pregnancy must be performed and be negative in all women of child bearing potential within 2 weeks prior to enrollment; because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with SAMe, breastfeeding should be discontinued if the mother is treated with SAMe
* Subjects with any medical psychosocial condition that, in the opinion of the investigator, could jeopardize the subject's participation in and compliance with the study criteria