BRAF and thyroid tumor: Follow-up ultrasound scan showed that thyroid tumors in homozygous Usp44 knockout mice (Braf m/+; Usp44-/-) grew more rapidly than that in Usp44 wild-type mice (Braf m/+; Usp44+/+) at tenth week (Fig. 4G; Fig. S2D), consistent with the gross appearance following dissection (Fig. 4H).