RNF40 and nasopharyngeal carcinoma: Western blotting analysis of the expression of RNF20, RNF40 and Eg5 in NPC (normal pancreatic cells), CFPAC-1, PANC-1, BxPC3, MCF-10A, MDA-MB-231, MCF-7, U2OS, SAOS-2, A549, H1299 and EPP85 cells showed a positively correlated pattern of expression between the RNF20/40 complex and Eg5 (Fig. 6a).