Cohorts of 1-6 patients receive escalating doses of bortezomib until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose-limiting toxicity. Up to 6 additional patients receive bortezomib at the MTD. Subsequent cohorts of 3-6 patients receive escalating doses of SAHA until the MTD of that drug is determined.