Question

How might the loss of components of the apoptosis
machinery render cancer cells more susceptible than normal cells to certain types of cell death?

Answer 1

Defects in programmed apoptosis mechanisms play important roles in tumor pathogenesis, allowing neoplastic cells to survive over intended lifespans, subverting the need for exogenous survival factors and providing protection from oxidative stress and hypoxia as the tumor mass expands. That gives time for accumulation of genetic alterations that deregulate cell proliferation, interfere with differentiation, promote angiogenesis, and increase invasiveness during tumor progression . Apoptosis defects are now considered an important complement of protooncogene activation, as many deregulated oncoproteins that drive cell division also trigger apoptosis (e.g., Myc, E1a, and Cyclin-D1) . On the other hand, the noncancerous cells have a DNA repair machinery. Defects in DNA repair and/or chromosome segregation normally trigger cell suicide as a defense mechanism for eradicating genetically unstable cells and thus such suicide mechanism