Consistently, the protein levels of STAT3 downstream target genes Bcl-xl, c-Myc, Pcna, and Ccnd1, which were responsible for tumor cell survival and proliferation, respectively4,37, were dramatically downregulated in colon tumors of TRIM27-deficient mice compared to their wild-type littermates (Fig. 8d). Here, PCNA is linked to colonic neoplasm.