CD69 and neoplasm: The basal level of CD69 in NK cells from tumor-bearing C57BL/6 mice was greater than that of NK cells from tumor-free mice (Fig. 4A–C). CD69 expression was downregulated by sorafenib (30 mg·kg·−1day−1 and 60 mg·kg−1·day−1, 2 weeks) in tumor-bearing C57BL/6 mice but not in tumor-free mice.