Statement: Patients in the primary trial receive vorinostat at the same frequency, dosage and through the same route of administration as the secondary trial receive 6-Mercaptopurine.
Primary_evidence: INTERVENTION 1:    Treatment (Enzyme Inhibitor Therapy, AI Sensitization Therapy)   Patients receive vorinostat PO QD for 2 weeks followed by AI therapy comprising anastrozole PO QD, letrozole PO QD, OR exemestane PO QD for 6 weeks. Courses repeat every 8 weeks in the absence of disease progression or unacceptable toxicity.   vorinostat: Given PO   laboratory biomarker analysis: Correlative studies   biopsy: Optional correlative studies   F-18 16 alpha-fluoroestradiol: Correlative studies   positron emission tomography: Correlative studies   anastrozole: Given PO   letrozole: Given PO   exemestane: Given PO   gene expression analysis: Correlative studies
Secondary_evidence: INTERVENTION 1:    6-Mercaptopurine and Methotrexate (6MP/MTX)   6-Mercaptopurine: 6MP 75mg/m2 body surface area, administered orally (PO) once a day (od) in the morning 1 hour after eating, on a continuous schedule. One cycle is 28 days. Treatment is given continuously until disease progression.   Methotrexate: Methotrexate 20mg/m2 will be taken orally, once a week, in the morning. One cycle is 28 days. Treatment is given continuously until disease progression.   Update: These original doses were reduced following an Urgent Safety Measure in August 2012 due to a large proportion of patients requiring a dose reduction or treatment delay due to incidences of myelo-suppression.   The reduced doses were 55mg/m2 of 6MP orally once a day, and 15mg/m2 of Methotrexate orally once a week.