SSTR4 and neoplasm: Whereas 54.8% of BP-NEN tumours were SST4-positive and the overall median IRS was 3.0 (mean ± S.E.M.: 3.41 ± 0.27), corresponding to very low expression, only 32.2% of GEP-NEN cases were SST4-positive and the overall median IRS was 1.5 (mean ± S.E.M.: 2.22 ± 0.18), corresponding to no expression.