61.   But if doctors know exactly which gene is causing the cancer, then they can go after only cells in which those genes are active.

62.   But in tests in more recent years, the FDA found that the drug may cause cancer.

63.   But MTBE has been shown to cause cancer in animals, even though it is not clear to researchers if those findings are applicable to people.

64.   But others, like an earlier one that suggested that coffee caused pancreatic cancer, turned out to be wrong when further studies were carried out.

65.   But researchers were surprised to find that it can also cause pancreatic cancer.

66.   But there is evidence that some of them can cause cancer.

67.   But there are fears the cancer-derived cells could cause cancer and that cells from pigs could infect patients with animal viruses.

68.   But when it becomes crumbly, airborne and inhaled, it can lodge in body tissues, where it can sometimes cause cancer.

69.   But while stress does not appear to cause cancer, there is evidence it may contribute to some problems.

70.   Caffeic acid causes cancer in laboratory animals, but its role, if any, in human cancer is unknown.