Both Dr. Gallo and Dr. Montagnier, who had devoted their careers to studying retroviruses, were cancer researchers. Before the appearance of AIDS, both men had vainly strived to implicate retroviruses as the culprit in leukemia. In 1975, before he ever published a paper on the subject, Gallo gained national headlines when he publicly announced his discovery of a human retrovirus HL-23 that he claimed caused leukemia.13
