GRP and glioblastoma: In another study of six human glioblastoma cell lines (U-138, U-118, U-1242, U-87,U-372, U-563), all expressed GRPR receptors detectable by binding studies; however, in none was immunoreactive BN/GRP-related peptide detected (<0.1 pmol mg protein on radioimmunoassay) (141).