But it is not clear whether the virus causes tumors in people.

Several of the chemicals have been found to cause tumors in laboratory animals.

However, vaccines can also cause tumors if not given properly.

Several research groups are investigating cancer stem cells and their potential to cause tumors.

It is not known how non-ionizing radiation might cause tumors.

There is some concern that extremely high doses for long periods of time (more than three years) can cause tumors.

Nearly 40 percent of people surveyed said they believed that exposure to air in surgery caused tumors to spread.

An unfortunate side effect of this ability is the strain it puts on the body can cause inoperable tumors.

He retired early to care for his wife, but died of a tumour caused by breathing in asbestos dust.

There is no doubt that SV40 causes tumors in rodents.