A retrospective study conducted by Sampson et al. examined possible reasons for the failures of the PRECISE (Phase III Randomized Evaluation of CED of IL13-PE3QQR with Survival Endpoint) trials and concluded that inadequate drug delivery volume to the tumor may have been an important indicator for the failure of the trial, as on average only 20.1% of the 2 cm penumbra surrounding the tumor resection cavity was covered by the drug [17]. The gene discussed is IL13; the disease is neoplasm.