Upper panels: a single cell with a relatively higher fitness expands at the expense of neighboring homotypic cells (i.e., cells of the same tissue type). The higher fitness of the rare cell could result from a relative loss in surrounding counterparts, as it occurs in aging [70,71]. Clones maintain cooperative capacity and expand within tissue boundaries.
Lower panels: a single cell with a relatively higher fitness and loss of cooperative capacity expands forming a focal proliferative lesion with histological alterations. These cells display growth autonomy (uncontrolled growth) and revert back to cell-centered competition, fueling clonal evolution.