Study to Assess Food Effect on Pharmacokinetics of Entinostat in Subjects With Breast Cancer or Non-Small Cell Lung Cancer

Inclusion Criteria: Breast Cancer Patients Only * Postmenopausal female patients * Histologically or cytologically confirmed ER+ breast cancer at initial diagnosis and now has current disease progression and is a candidate to receive exemestane NSCLC Patients Only: * Cytologically or histologically confirmed NSCLC of stage IIIb or IV * Received 1 to 2 prior chemotherapy or chemoradiotherapy regimens for advanced NSCLC (excluding erlotinib and valproic acid) and now has disease progression and is a candidate to receive erlotinib All Patients: * Age ≥ 18 years * Patient must have the following laboratory parameters at study screening: Hemoglobin ≥ 9.0 g/dL; unsupported platelets ≥ 100.0 10-9/L; ANC ≥ 2.0 x 10-9/L; Creatinine less than 2.5 times the upper limit of normal for the institution; AST and alanine transaminase (ALT) \< 2.5 times the upper limit of normal for the institution * Patients may have a history of brain metastasis as long as certain criteria are met Exclusion Criteria: * Pregnant or lactating women * Patient has rapidly progressive or life-threatening metastases. * Patient has had previous treatment with entinostat or any other HDAC inhibitor including valproic acid * Patient has a concomitant medical condition that precludes adequate study treatment compliance or assessment, or increases patient risk in the opinion of the investigator, such as but not limited to: MI or arterial thromboembolic events within 6 months, or experiencing severe or unstable angina, New York Heart Association (NYHA) Class III or IV disease and a QTc interval \> 0.47 seconds. Uncontrolled heart failure or hypertension, uncontrolled diabetes mellitus, uncontrolled systemic infection. * Patients with another active cancer (excluding adequately treated basal cell carcinoma or cervical intraepithelial neoplasia \[CIN / cervical carcinoma in situ\] or melanoma in situ). Prior history of other cancer is allowed, as long as there is no active disease within the prior 5 years.