The immune system of individuals with AIDS is severely compromised and weak, so the body cannot fight off certain bacteria, viruses, fungi, parasites, and other microbes. Opportunistic infections can easily establish themselves. In addition, people with AIDS are prone to developing various cancers, especially those caused by viruses such as Kaposi’s sarcoma and cervical cancer, or cancers of the immune system known as lymphomas. These cancers are usually more aggressive and difficult to treat in people with AIDS.