Cancer Stem Cells, Loss of Function, and Stemness Recovery; Generation of New Functional Stem Cells in Cancer Cell Systems

The evolutionary cancer cell biology ECCB explains the deep homology existent between the life cycle of cancer and protists. Due to their origin and sensitivity to oxygen, all non-gametogenic germ lines and germ stem cells (GSCs), including human adult stem cells (ASCs) and cancer stem cells (CSCs), suffer severe DNADSB damage when exposed to stress oxygen content above 6.0% O2 (Urgermline hyperoxia) as occurring in tissue and bloodstream. As a result, GSCs/ASCs/ CSCs lose their stemness potential and convert from a functional asymmetric cyclic phenotype (ACD phenotype) to a dysfunctional symmetric phenotype capable of defective symmetric proliferation (DSCD) that is, however, unable to repair genomic degradation. Genome reconstruction occurs through evolutionary mechanisms evolved by the common ancestor of amoebozoans, metazoans, and fungi. They complete the cycle by removing the damage, reconstructing the functional genome, and reinstating the ASC phenotype. The stemness life cycle acts not only during carcinogenesis, tumorigenesis, and recurrence but also in the life cycle of protists.