Phase II trial to explore the efficacy of vorinostat and tamoxifen combined. Tamoxifen will be given once daily, continuously. Vorinostat will be given daily for 3 out of 4 weeks (a cycle). Responses will be assessed (restaged) after 2 cycles and toxicities will be captured continuously. Eligible patients will receive treatment in consecutive 4-week cycles, until progression of disease or unacceptable toxicity. Patients will be followed for evaluation of safety for at least 30 days after the last dose of the study drug.