Various cancer-causing substances are associated with primary liver cancer, including certain herbicides and chemicals such as vinyl chloride and arsenic. Smoking , especially if you abuse alcohol as well, also increases risk. Aflatoxins, cancer-causing substances made by a type of plant mold , have also been implicated. Aflatoxins can contaminate wheat, peanuts, rice, corn, and soybeans. These are rare problems in most developed countries like the . Other causes include the hormones androgen and estrogen and a dye formerly used in medical tests called thorotrast.