Next, we performed IHC assays to assess the levels of Usp44 and Ki-67 in the above thyroid tumor tissues and found that Braf m/+/Usp44-/-mice had lower levels of Usp44 but higher levels of Ki-67 than Braf m/+; Usp44+/+ mice (Fig. 4J; Fig. S2E). Here, USP44 is linked to thyroid tumor.