<qa>  What is the potential for a drug development problem?A significant problem in drug development of novel small molecules is the lack of available tissues surrogate tissues that allow for the assessment of the molecular and biochemical effects of targeted-therapies drug action. The information obtained from surrogate tissues might help us validate previous preclinical studies with those agents and also dose them in a more rational way. Oral keratinocytes, which are accessible by non-invasive means, might be useful to assess drug action. The proposed study seeks to investigate the genetic, molecular, and biochemical effects of novel agents in oral buccal mucosal cells. Patients already enrolled in Phase I and II clinical trials for neoplastic diseases at the Clinical Center will undergo oral cytobrushing before and during therapy to determine the molecular and biochemical effects of novel agents in the oral mucosa cells. Similar studies will be performed in peripheral blood mononuclear cells. In order to validate to compare and compare the oral cytobrush methodology, some of these subjects will undergo oral punch biopsy studies. Some of these subjects will also undergo tumor biopsy, if accessible or available. 