Aging (Senescence) , Telomeres, Hayflick limit and Cancer risk

http://en.wikipedia.org/wiki/Replicative_senescence The Hayflick limit[Note 1] (or Hayflick phenomenon) is the number of times a normal human cell population will divide until cell division stops. Leonard Hayflick demonstrated that a population of normal human fetal cells in a cell culture will divide between 40 and 60 times. Telomeres associated with each cell's DNA will get slightly shorter with each new cell division until they shorten to a critical length and can no longer divide, entering a senescence phase. Postulation : Cancer cells must all have a way of exceeding the Hayflick limit. Many will produce an enzyme called telomerase to allow lengthening of telomeric DNA. In an aging cell population there may be a high proportion of cells already capable to producing telomerase as a way of allowing a tissue to produce new cells. Logical deduction : Any substance such as chlorine, which kills human cells, will cause aging of an exposed tissue by causing increased cell division.