RT Journal Article SR Electronic T1 Health and Fitness at the Single-Cell Level JF Cancer Immunology Research JO Cancer Immunol Res FD American Association for Cancer Research SP 130 OP 135 DO 10.1158/2326-6066.CIR-20-0418 VO 9 IS 2 A1 Green, Douglas R. YR 2021 UL http://cancerimmunolres.aacrjournals.org/content/9/2/130.abstract AB Genetically identical cells in a tissue can respond differently to perturbations in their environment or “stress.” Such stresses can be physicochemical, mechanical, or infectious or may come from competition with other cells in the tissue. Here, I discuss how the varying responses to stress influence the decision of a cell to repair or die, and how one cell's response can have effects on surrounding cells. Such responses control the health and fitness of single cells and how they compete with other genetically identical cells.See related article on p. 129