In one study of human glioblastoma U-87MG cells (160), both GRPR and NMBR mRNA was found; however, GRP mRNA was not found, leading the authors to speculate that the GRP effect on these tumor cells was likely mediated by a paracrine mechanism, although no additional studies were performed to establish what cells might be secreting the GRP. The gene discussed is NMBR; the disease is glioblastoma.