The biological and clinical significance of aberrant clonal expansions in aged tissues is being intensely discussed. Evidence is accruing that these clones often result from the normal dynamics of cell turnover in our tissues. The aged tissue microenvironment is prone to favour the emergence of specific clones with higher fitness partly because of an overall decline in cell intrinsic regenerative potential of surrounding counterparts. Thus, expanding clones in aged tissues need not to be mechanistically associated with the development of cancer, albeit this is a possibility. We suggest that growth pattern is a critical phenotypic attribute that impacts on the fate of such clonal proliferations. The acquisition of a better proliferative fitness, coupled with a defect in tissue pattern formation, could represent a dangerous mix setting the stage for their evolution towards neoplasia.

衰老组织中异常克隆扩增的生物学和临床意义正在得到热烈讨论。越来越多的证据表明，这些克隆通常是由我们组织中细胞更新的正常动态产生的。老化的组织微环境很容易有利于具有更高适应度的特定克隆的出现，部分原因是周围对应物的细胞内在再生潜力总体下降。因此，衰老组织中克隆的扩增不一定与癌症的发展存在机械关联，尽管这是一种可能性。我们认为生长模式是影响此类克隆增殖命运的关键表型属性。获得更好的增殖适应性，加上组织模式形成的缺陷，可能代表着一种危险的组合，为它们向肿瘤的进化奠定了基础。