FEN1 and neoplasm: For instance, in “DPD →Final”, there is a significant synergism between the not-regulated FEN1 and REC1 in the PTC nodule of the tumor ((COR = 0.978; (Figure 6b)), but also between the up-regulated FEN1 and the down-regulated REC1 in the BCPAP cells (COR = 0.951; Figure 6c).