DNA replication factors cell division cycle 6 (CDC6), chromatin licensing and DNA replication factor 1 (CDT1), mini chromosomal maintenance complex (MCM2, MCM4, MCM6, MCM7) and CDC45 were all significantly up-regulated in tumor samples compared with the adjacent mucosa of the same patient (p < 0.001, Fig. 1). This evidence concerns the gene MCM4 and neoplasm.