The main purpose of this study is to determine the safety and tolerability of orally administered CUDC-101 in cancer patients, and to determine a dose for further testing. This study will also determine how well CUDC-101 is absorbed into the blood after being given orally, assess CUDC-101 blood levels and what happens to the study drug in the body, and study how the body reacts to the study drug and what effects it has on tumors. CUDC-101 has been administered to cancer patients as an intravenous (IV) infusion in other research studies, but has not been studied when given orally.

Inclusion Criteria:

1. Subjects with a histopathologically confirmed diagnosis of advanced solid tumor.
2. Subjects must have no further standard of care options.
3. Measurable or non-measurable disease
4. Age ≥ 18 years
5. ECOG performance status ≤ 2
6. Life expectancy ≥ 3 months
7. Women of child bearing potential must have a negative serum pregnancy test.
8. Absolute neutrophil count ≥ 1,500/µL; platelets ≥ 100,000/µL; creatinine ≤ 1.5x upper limit of normal (ULN); total bilirubin ≤ 1.5x ULN; AST/ALT ≤ 2.5x ULN. For subjects with documented liver metastases, the AST/ALT may be ≤ 5x ULN
9. Serum magnesium and potassium within normal limits (may be supplemented to achieve normal values).
10. Subjects with brain metastases are eligible if controlled on a stable dose of ≤ 10mg prednisone/day or its equivalent dose of steroids.
11. Men and women of child bearing potential must agree to use adequate birth control throughout their participation in the study and for 60 days following the last study treatment.
12. Able to provide written informed consent and to follow protocol requirements.

Exclusion Criteria:

1. Systemic anticancer therapy within 28 days prior to study treatment. Subjects with prostate cancer on LHRH hormonal therapy may be enrolled and continue on this therapy.
2. Use of any investigational agent(s) within 21 days prior to study treatment.
3. Known human immunodeficiency virus (HIV) positive, hepatitis B surface antigen-positive, or known or suspected active hepatitis C infection.
4. Subjects receiving moderate or strong CYP3A4 or CYP2D6 inhibitors within 7 days prior to study treatment (See Appendix C for examples).
5. Serious infection requiring systemic antibiotic therapy within 14 days prior to study treatment.
6. Known gastrointestinal condition that would interfere with swallowing or the oral absorption or tolerance of CUDC-101.
7. Ongoing diarrhea of any grade (per NCI CTCAE v4.03).
8. Uncontrolled or severe cardiovascular disease, including myocardial infarct or unstable angina within 6 months prior to study treatment, New York Heart Association (NYHA) Class II or greater congestive heart failure, serious arrhythmias requiring medication for treatment, clinically significant pericardial disease, or cardiac amyloidosis.
9. Unstable or clinically significant concurrent medical condition that would, in the opinion of the Investigator, jeopardize the safety of a subject and/or their compliance with the protocol.