- Patients must agree to undergo two research biopsies of (a) malignant lesion(s). The investigator must also judge that the patient has tumor(s) safely accessible for biopsy. Patients may be exempt from the second biopsy if after the performance of the first biopsy it is felt that a second biopsy would be unsafe for the patient. If the patient has only one RECIST measureable target lesion for response assessment, research biopsies must not be performed on that target lesion.