RNF6 and neoplasm: When tumors reached ~50 mm3, mice were randomized into four groups as follows: PBS, 5-FU, pladienolide B, and 5-FU + pladienolide B. As shown in Fig. 6E, F, 5-FU plus pladienolide B synergistically induced the tumor regression of HCT116-RNF6 xenografts compared to control or single drug treatment in vivo, both in terms of tumor weight (P < 0.001) and volume (P < 0.001).