'Mob Wives' Star Big Ang -- Throat Tumor Is Cancerous

"Mob Wives" star Big Ang received the news she was dreading -- the tumor on her throat is malignant.

Ang’s sister, Janine Detore, tells TMZ the tumor is on Ang's voicebox and her voice is deteriorating as a result. She says doctors determined the lemon-sized growth was cancerous after looking at it with a scope and running blood tests.

Janine says the family is awaiting results of another test to determine if the cancer has spread.

There's no history of cancer in the family, but Janine says they fear Ang's 42 years of smoking might have contributed. She adds ... doctors have ordered Ang to quit smoking immediately.

None of the ordeal has been filmed for "Mob Wives" ... but Janine says it might be addressed on the show at some point. Ang is scheduled to have surgery next week to remove the tumor.

Janine says, "We are hoping for the best and are focusing on getting through the holiday. We love the fans and want to thank them."