PCNA and neoplasm: Similarly to galectin-3, the expression of proliferating cell nuclear antigen (PCNA) that is associated with enhanced tumor cell proliferation and invasive potential, leads to the inhibition of NK cell function via binding to activating NCR receptor NKp44 (Rosental et al., 2011; Rusakiewicz et al., 2017; Krijgsman et al., 2020).