another cis-eGene in 9q22, TRMO, for both trans-eGenes43 (posterior probability >0.99). Mendelian randomization analysis of the PEER-corrected data supported the idea that TRMO regulates TMEM253 (P ≤1.3×10−9) and ARFGEF3 (P ≤2.1×10−11) based on trans-eVariant rs1867277. By contrast, FOXE1 had weak Mendelian randomization support in the PEER-corrected data. Despite the ambiguity of cis-mediation, the locus is one of the strongest trans-eQTL signals in GTEx. We further replicated both the broad regulatory effect and specific target genes of this locus in 498 primary thyroid cancer RNA-seq samples from The Cancer Genome Atlas50 (TCGA; Fig. 6b, Supplementary Information 18).
