However, two senior Egyptian medical officials - one of them the head of Mubarak's team of doctors - said he does not have the disease.
The 83-year-old has been hospitalized with heart troubles since April at a resort town on the Red Sea.
Mubarak had surgery for cancer found in his gallbladder and pancreas last year. His attorney said this may be a recurrence, and it may have reached his stomach.
He is scheduled to face trial in August on allegations he ordered the killing of anti-government protesters during the 18-day uprising that ousted him on Feb. 11.
Some activists see remarks about his health as a ruse to revive calls for Mubarak to get amnesty.
Assem Azzam, the head of Mubarak's medical team in the Sharm el-Sheikh hospital, told The Associated Press, "All medical checkups show that he doesn't have cancer. This is not true at all."
"His condition in general is stable," he added.
Another top medical official in the Sharm hospital confirmed that Mubarak is only suffering from heart troubles.
The Associated Press contributed to this report.