HALIFAX -- Tuxedo Stan, the cat who gained worldwide attention when he ran for mayor of Halifax, is battling a serious illness.

Owner Hugh Chisholm says Tuxedo Stan is resting at home after undergoing treatment for kidney cancer at a veterinary college in Charlottetown.

Chisholm said Tuxedo Stan was admitted to hospital this week after the discovery of a large mass in his abdomen, which turned out to be a cancerous tumour on his left kidney.

Chisholm said the 2 1/2 year old, black and white cat will continue treatment for renal lymphoma, a type of cancer that is not uncommon in older cats.

"His prognosis is guarded because it is an aggressive form of lymphoma," said Chisholm.

"But he's got a few things going in his favour. So far it only appears to be affecting one kidney and he is in generally good health otherwise and his age is certainly in his favour."

He said Tuxedo Stan is receiving hundreds of messages of support through his Facebook and website pages.

"He's getting comments not just from Nova Scotia but from across Canada and around the world. People in Australia, Europe and Asia."

The cat ran in last fall's municipal election to raise awareness about the plight of stray cats in the city.

The campaign drew media attention that was magnified after it was endorsed by talk show host Ellen DeGeneres and CNN's Anderson Cooper.