Fig. 3
From: Retinocytoma: understanding pathogenesis, diagnosis, and treatment approaches
Knudson’s two-hit hypothesis. If the first mutation is present in the germline, all somatic cells will carry one mutant allele. This increases the probability of a second mutation occurring during the somatic stage, which can affect multiple retinocytes in both eyes and other somatic precursor cells. If both mutations occur during the somatic stage, it leads to the development of unilateral unifocal retinoblastoma. Figure generated using BioRender