Regulators of mammalian cell growth have been identified (e.g. mTORC1). But, how are these regulators programmed to specify and different and specific side for each of the different human cell types?

Can drugs that increase lifespan negate cancer risk in predisposed individuals?

In literature, mechanisms of longevity have been characterized. Examples include mTORC1 signaling and senescence. Yet, the following remains unclear. How does a diversity of mechanisms converge to reproducibly specify a different characteristic lifespan value for each of the different mammalian species? Why do mice die of old age after three years of life while fruit bats live to the age of forty?

How are signal transduction pathways programmed to specify definite values? (e.g. cell size, lifespan and cancer risk)