DICER1 and neoplasm: Although thyroid tumors weights from RET/PTC3 Dicer1(+/+) and RET/PTC3 Dicer1(+/−) mice were not significantly different, RET/PTC3 Dicer1(−/−) tumors exhibited slightly slower growth curves and reduced tumor weight at 4 and 8 months of age (Figure 3B,C).