Genomic landscape of FGF/FGFR pathway alternations across 12,372 pan-cancer patients.

e13503 Background: The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling pathway is involved in diverse biological processes and plays a crucial role in carcinogenesis. FGFR targeted therapies have shown great promise in the treatment of a multitude of malignancies. This study aimed to assess the alternations of FGF/FGFR pathway and explore the potential relationships between the genetic alternations in a pan-cancer setting. Methods: Next-generation sequencing was conducted with formalin-fixed, paraffin-embedded tumor specimens from 12,372 Chinese cancer patients with over 21 tumor types, including lung cancer (n = 3557), liver cancer (n = 1433), colorectal cancer (n = 1310), biliary tract cancer (n = 960), gastric cancer (n = 758), etc. Somatic mutations including single nucleotide variations (SNVs), amplifications, and fusions were analyzed, and microsatellite instability status was also assayed. Results: Of all patients, the frequency of genomic alterations in FGF/FGFR pathway (FGF3/4/6/10/14/19/23 and FGFR1-4) ranged from 54.1% (86/159) in esophagus cancer, 40.7% (112/275) in bladder/urinary tract cancer, 28.4% (73/257) in head and neck cancer to 5.3% (5/95) in prostate cancer and 4.0% (22/548) in kidney cancer. Amongst all, the highest mutational prevalence fell in FGFR SNV (5.13%) and FGF amplification (5.08%), followed by FGF SNV (3.90%), FGFR amplification (2.89%), FGFR fusion (0.88%), and FGF fusion (0.06%). Partial co-occurrence was observed between alternations of FGFR1 and 11q13 (FGF3/4/19) and between FGF6 and FGF23. On the other side, alternations of FGFR1, FGFR2, FGFR3, and FGFR4 were found to be mutually exclusive ( p< 0.001). In addition, microsatellite instability was found to be positively correlated with FGF/FGFR pathway mutation ( p< 0.001), while was negatively correlated with pathway amplifications ( p= 0.002). Conclusions: Our study investigated the molecular landscape of FGF/FGFR pathway alternations and the interplay between co-occurrence and mutual exclusivity between pathway genes in a large pan-cancer cohort. FGF/FGFR pathway mutations occurs in a variety of solid tumors, indicating that these patients may benefit from FGFR inhibitors.