61.   One reason for skepticism about curing AIDS is that the virus integrates itself into the machinery of normal cells.

62.   Other tumor-suppressing genes, Holt noted, also tend to slow the growth of normal cells which makes them less desirable as a cancer therapy.

63.   Probably four or five separate genes must be knocked out before a normal cell becomes a fully developed tumor cell.

64.   Scientists call it molecular targeting because drugs home in on chemical signals that can turn a normal cell into a cancer.

65.   Researchers from Geron and from the University of Texas Southwestern Medical Center at Dallas say that by grafting a rare enzyme into normal human cells.

66.   Scientists were learning how the cancer cell differs from normal cells, an understanding that often was advanced as much through their failures as their successes.

67.   Scientists say that gene therapy makes more sense than radiation because it takes direct aim at cancer cells while leaving normal cells intact.

68.   Some studies have found that normal cells divide in the morning, while cancerous cells divide throughout the day.

69.   Such a cancer therapy in theory would be relatively nontoxic, because normal cells, lacking telomerase, would not be attacked.

70.   The added oncogene goaded normal pancreatic cells into uncontrolled growth, going through a number of stages leading to tumors that grew until they eventually killed the mice.