Validation studies using PCR, performed in 73 specimens, confirmed the RNA-seq results indicating the differential expression of COL11A1, MUC12, FRMD5, FCGBP, EGFL6, FN1, KLK5, ITGA9, WNT4, WNT2, WNT16, CXCL13, CBX8, NDC80, NTM, PPP1R14C, JAK3, EZH2, IGFBPL1, MTMR8, ATP5MC1P1, HMX1, CYP19A1, RGS4, BMP7, DCX, and CACNA1D mRNA was significantly higher, while the expression of S100A1, RAB37, and S100A4 mRNA was significantly lower in MED12-mutated leiomyomas compared with non-mutated specimens. The gene discussed is CBX8; the disease is leiomyoma.