Supplementary Material for: Gly388Arg FGFR4 Polymorphism Is Not Predictive of Everolimus Efficacy in Well-Differentiated Digestive Neuroendocrine Tumors

<b><i>Introduction:</i></b> Preclinical data suggest that the single nucleotide polymorphism substituting a glycine for an arginine in codon 388 of the FGFR4 transmembrane domain may increase the proliferation of xenografted neuroendocrine cell lines and decrease their sensitivity to everolimus by modulating STAT3 signaling and the mTOR pathway. <b><i>Aim:</i></b> To evaluate the prognostic and predictive values of this polymorphism on everolimus efficacy in patients treated for digestive neuroendocrine tumor (NET). <b><i>Patients and Methods:</i></b> This monocentric retrospective cohort included patients with small bowel NET (SBNET) and pancreatic NET (PNET) treated with everolimus (2006-2013). The patients were genotyped by classical sequencing, and mTOR pathway activity was assessed by immunochemistry on formalin-fixed paraffin-embedded samples (PTEN/pPTEN/pAKT/pmTOR/pS6/p4EBP1). <b><i>Results:</i></b> Forty-one patients (21 males, median age 57 years) with PNET (n = 28), SBNET (n = 12) or NET of unknown origin (n = 1), grade 1 (n = 8), 2 (n = 27), 3 (n = 3) or unknown grade (n = 3), were studied. At least one 388Arg allele was found in 14/23 PNET and 10/11 SBNET. Progression-free survival in the whole population and the PNET subgroup was not influenced by the presence of one or two 388Arg alleles [HR = 1.31 (0.58-2.99), p = 0.52 and HR = 1.11 (0.45-2.73), p = 0.82, respectively]. Similarly, overall survival was not influenced. Finally, mTOR pathway molecule expression was not modified by the presence of at least one 388Arg allele. <b><i>Conclusion:</i></b> The Gly388Arg FGFR4 polymorphism does not seem to have a prognostic value in digestive NET. In addition, it neither predicts the response to everolimus nor modifies the activation of the mTOR pathway.

**引言：** 临床前研究数据显示，成纤维细胞生长因子受体4（FGFR4）跨膜结构域388位密码子处发生的甘氨酸替代精氨酸单核苷酸多态性，可通过调控信号转导与转录激活因子3（STAT3）信号通路及哺乳动物雷帕霉素靶蛋白（mTOR）通路，促进异种移植神经内分泌细胞系的增殖，并降低其对依维莫司的敏感性。**研究目的：** 本研究旨在评估该单核苷酸多态性对接受依维莫司治疗的消化神经内分泌瘤（NET）患者的预后价值与预测价值。**患者与方法：** 本单中心回顾性队列纳入2006年至2013年间接受依维莫司治疗的小肠神经内分泌瘤（SBNET）与胰腺神经内分泌瘤（PNET）患者。研究采用经典测序法对患者进行基因分型，并通过免疫组织化学法检测福尔马林固定石蜡包埋样本中的mTOR通路活性，检测指标包括PTEN/pPTEN/pAKT/pmTOR/pS6/p4EBP1。**结果：** 本研究共纳入41例患者（21例男性，中位年龄57岁），其中胰腺神经内分泌瘤（PNET）28例、小肠神经内分泌瘤（SBNET）12例、来源不明神经内分泌瘤1例；肿瘤分级为1级8例、2级27例、3级3例、分级不明3例。在23例可检测的PNET患者中，14例携带至少1个388Arg等位基因；在11例可检测的SBNET患者中，10例携带至少1个388Arg等位基因。全人群与PNET亚组的无进展生存期不受携带1个或2个388Arg等位基因的影响[风险比（HR）=1.31（95%置信区间：0.58~2.99），p=0.52；HR=1.11（95%置信区间：0.45~2.73），p=0.82]。总生存期同样未受该等位基因携带情况的影响。此外，携带至少1个388Arg等位基因不会改变mTOR通路分子的表达水平。**结论：** FGFR4基因Gly388Arg单核苷酸多态性对消化神经内分泌瘤（NET）似乎并无预后价值。此外，该多态性既无法预测患者对依维莫司的治疗应答，也不会改变mTOR通路的激活状态。