Transhuman / Ben Bova.

"A Tom Doherty Associates Book."

Luke Abramson, a brilliant cellular biologist who is battling lung cancer, has one joy in life, his ten-year-old granddaughter, Angela. When he learns that Angela has an inoperable brain tumor and is given less than six months to live, Abramson wants to try a new enzyme, Mortality Factor 4 (MORF4), that he believes will kill Angela's tumor. However, the hospital bureaucracy won't let him do it because MORF4 has not yet been approved by the FDA. Knowing that Angela will die before he can get approval of the treatment, Abramson abducts Angela from the hospital with plans to take her to a private research laboratory in Oregon. Luke realizes he's too old and decrepit to flee across the country with his sick granddaughter, chased by the FBI. So he injects himself with a genetic factor that will stimulate his body's production of telomerase, an enzyme that has successfully reversed aging in animal tests. As the chase weaves across the country from one research facility to another, Luke begins to grow physically younger, stronger. He looks and feels the way he did thirty or forty years ago. Yet his lung cancer is not abating; if anything the tumors are growing faster. And Angela is dying.