The Food and Drug Administration said a study of the gel, called Regranex, found an increase in the number of cancer deaths among patients who had been prescribed the gel three or more times.

Regranex, approved for U.S. patients in 1997, is a prescription gel used to treat diabetic leg and foot wounds.

"At this time, FDA believes that there may be some evidence for an increased risk of death from cancer in patients who had repeated treatments with Regranex," the FDA said in a statement. "Because there are known risks associated with diabetic foot and leg ulcers that do not heal, the potential risk of using Regranex should be weighed against the benefit for each individual patient."

Barbara Montresor, a spokeswoman for Johnson & Johnson's Ethicon Inc unit that makes the gel, said the company was working with the agency and that Regranex is safe when used as directed.

Patients with diabetes -- a disease in which blood levels of sugar are too high -- are more susceptible to developing leg and foot wounds because they are less able to feel their feet.

Concern arose following a study of adult diabetes patients through an insurance plan database that found an increase in cancer deaths from January 1998 through June 2003. No single type of cancer was identified, the FDA said.