While FIH expression status did not affect the lifespan of the experimental animals (Fig. 1A; upper case N denotes number of mice hereafter), necropsy analyses revealed that FIH+/Δ1-2 and FIHΔ1-2/Δ1-2 mice displayed accelerated tumor onset compared with FIH+/+ mice (FIH+/+ vs. FIH+/Δ1-2P = 0.0351, FIH+/+ vs. FIHΔ1-2/Δ1-2P = 0.0358 by the Mantel–Cox test) (Fig. 1B). This evidence concerns the gene CASR and neoplasm.