...validated the predictive results of experimental studies in a group of patients treated with everolimus...patients homozygous for FGFR4-G388 had a median PFS of 16.6 (95%CI: 10.8–22.3) months, whereas those harboring an FGFR4-R388 allele had a median of 4.8 (95%CI: NA − 10.2) months (Fig. 4B, P = 0.40). Median OS was 27.4 (95%CI: 7.2–47.6) months. When separated by genotype, patients homozygous for FGFR4-G388 had a median OS of 40 (95%CI: 19.5–60.5) months, whereas those harboring an FGFR4-R388 allele had a median OS of 9.3 (95%CI: NA–21.9) months...FGFR4-R388 is associated with more aggressive clinical behavior in patients with pNETs with a statistically significant higher risk of advanced tumor stage and liver metastasis.