Cancer or cancer-like phenomena pervade multicellular life, implying deep evolutionary roots. Many of the hallmarks of cancer recapitulate unicellular modalities, suggesting that cancer initiation and progression represent a systematic reversion to simpler ancestral phenotypes in response to a stress or insult. This so-called atavism theory may be tested using phylostratigraphy, which can be used to assign ages to genes. Several research groups have confirmed that cancer cells tend to over-express evolutionary older genes, and rewire the architecture linking unicellular and multicellular gene networks. In addition, some of the elevated mutation rate – a well-known hallmark of cancer – is actually self-inflicted, driven by genes found to be homologs of the ancient SOS genes activated in stressed bacteria, and employed to evolve biological workarounds. These findings have obvious implications for therapy.

癌症或类似癌症的现象普遍存在于多细胞生命中，这意味着其具有深厚的进化根源。癌症的许多特征都概括了单细胞模式，表明癌症的发生和进展代表着对压力或侮辱的反应，系统性地回归到更简单的祖先表型。这种所谓的返祖理论可以使用系统地层学进行测试，该系统可用于确定基因的年龄。几个研究小组已经证实，癌细胞倾向于过度表达进化上的旧基因，并重新连接单细胞和多细胞基因网络的结构。此外，一些突变率升高（众所周知的癌症标志）实际上是自己造成的，是由在压力细菌中激活的古代 SOS 基因的同源基因驱动的，并被用来进化生物解决方案。这些发现对治疗具有明显的意义。