Part One investigates monotherapy with oral hydroxyurea. The primary objective is to determine whether a tolerated dose (TD) of hydroxyurea as a single agent can increase the percentage of tumor cells in S and G2 phase of the cell cycle. For this reason, all patients in Part One must have a tumor lesion accessible for a skin punch biopsy. Tumor biopsies will be obtained on two separate occasions: prior to hydroxyurea and at 16-18h after starting hydroxurea therapy on day 1 only.