GDF15 and thyroid cancer: Based on the number of datasets at which each DEG was identified and the prognostic role of the DEGs, we categorized the DEGs as grade 1 (ETV5, FN1, and NRCAM), grade 2 (ABCC3 and ETV4), grade 3 (ALDH1A3, CKS2, GALE, GDF15, and GGCT), and grade 4 (MAMLD1, MAP4K4, PSD3, PTP4A3, TNFRSF10B, TNIK, TUSC3, and ZMAT3) levels of biomarker signatures of thyroid cancer pathogenesis.