 In this phase I pilot study, six patients with multiple myeloma or cutaneous lymphoma will be treated with ATRA plus G-CSF, and safety and toxicity data collected for the two week study drug period plus a further two weeks follow-up. The primary endpoint is safety and toxicity, the secondary endpoint is an observation of the mobilization efficacy as demonstrated by CD34 cell counts over the study period. Patients will not undergo stem cell collection during this study, as this is purely an observational study. Participating patients will not be those who would normally be scheduled for stem cell collection and transplantation in the near future, but rather patients with stable disease who are not candidates for imminent transplantation, or who have collected adequate HSPC on previous mobilization attempts and are currently being observed. 