Dear student,
Epstein Barr virus and HIV virus are the two biological carcinogens. Epstein Barr virus affects blood and bone marrow and causes B lymphocytes to change into lymphoblastoid cell lines which causes malignancies and cancer.
HIV virus affects the body's immune system and makes it weaker which leads to attack by various viruses making body prone to cancer. The viruses which attacks HIV infected patient are Epstein-Barr virus which causes hodgkin and non-hodgkin lymphoma. Human papillomavirus causes cervical cancer, anal cancer, vaginal cancer etc.
Regards