The concept of synthetic lethality. This figure illustrates the concept of synthetic lethality, wherein the viability of cells is contingent upon the loss of function (LOF) of either gene A or gene B individually. However, the simultaneous LOF of gene A and gene B results in cell death, indicating synthetic lethality. Consequently, the administration of a gene B inhibitor does not induce cell death in cells lacking gene A LOF, whereas tumor cells harboring gene A LOF experience cell death upon exposure to the gene B inhibitor.