GDNF and neoplasm: In both the KIRC and IARC tumour tissue data (P=0.002 and 0.03, respectively), the rs2241261 risk allele was associated with a decreased expression of GFRA2, which encodes for cell-surface receptor for glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN), and mediates activation of the RET tyrosine kinase receptor (Glial cell line-derived neurotrophic factor (Supplementary Data 4).