People with HIV have a greater risk of developing certain cancers because their immune systems are weakened and they become more vulnerable to illness. The most common cancers associated with HIV infection are Kaposi sarcoma (a type of cancer of the blood vessels) and cancers of the lymph nodes, cervix, uterus, anus, lung, vulva, vagina, penis, and liver. There is also an increased risk of cancers of the lip, mouth, and throat, and certain cancers of the skin.