Bovine Meat and Milk Factors

Bovine Meat and Milk Factors (BMMFs) are circular, single-stranded DNA molecules (cssDNAs), also termed plasmid-like, originally found in beef and cow's milk which have been linked to the development of cancer—particularly colorectal and breast cancer. They are formerly known as Slow Progressive Hidden INfections of variable X (SPHINX).

Source: Wikipedia — Bovine Meat and Milk Factors (CC BY-SA 4.0)