MAPK1 and thyroid cancer: In core signaling pathways of carcinogenic progression from normal thyroid cells to early-stage thyroid cancer cells shown in Figure 1, identified gene expression signature containing three abnormal downregulated genes—PDX1, JAM3, and NOV—and six abnormal upregulated genes—IL4, RAP2C, PARD6B, MAP2K1, CD151, and MAPK1.