MCM2 and MCM5 as Prognostic Markers in Colon Cancer: A Worthwhile Approach

摘要

In their current report, Theocharis and coworkers analyze the relation of MCM2 and MCM5 with clinicopathology parameters and molecular parameters of cell proliferation and differentiation well established in colon cancer . While they found MCM2 to be consistently associated with clini-copathological parameters, Ki67 and p53, MCM5 was not. What makes this study so appealing? Besides its concise and straight-forward character, it deals with an interesting molecular parameter, minichromosome maintenance proteins (Mem). The Mem family members (Mcm2-7) are highly conserved replication initiation factors. Mem proteins are presumed to regulate replication by cyclical DNA-unwinding. They are integrated into pre-replicative complexes forming during the Gl phase of the cell cycle. Thereby they "license" chromatin for replication in the subsequent S phase. While Mem proteins are present in all phases of the proliferative cell cycle, they are absent in quiescent cells and in cellular senescence. The strict relation to chromatin replication renders the Mem protein family a novel class of proliferation marker . They are currently viewed as highly specific for proliferation . In contrast to Ki67, which was also analyzed in the current contribution by Theocharis, Mcm2 is an essential factor for initiation of DNA replication in eukaryotic cells. Thus Mem proteins have been suggested as excellent markers for tumor evaluation