Two Landmark Studies Published in 1976/1977 Paved the Way for the Recognition of Human Papillomavirus as the Major Cause of the Global Cancer Burden

Two groundbreaking reports were published in Acta Cytologica at the transition of 1976 to 1977. One appeared in the last issue of 1976 [Meisels and Fortin: Acta Cytol 1976;20:505-509] and the other in the first issue of 1977 [Purola and Savia: Acta Cytol 1977;21:26-31]. Today, 40 years later, it is not an overstatement to conclude that these are the two most influential studies ever published in this journal. Two reports with a similar content being published so close together (in the same journal) raised the question “Which of the two reports was truly submitted first?” In this commentary, this enigma is clarified beyond reasonable doubt, based on the well-considered testimonial of Prof. Leopold G. Koss, the reviewer of one of the two papers. To fully appreciate the significance of the novel discovery made in these two reports, it is essential to align them in the right context, both retrospectively and prospectively. This commentary will assist the reader by summarizing the existing knowledge on human papillomavirus (HPV) before these two milestone papers appeared, and describe the incredibly rapid progress that they evoked during the subsequent decades, which made HPV the single most important human tumor virus. As the final proof of virus-cancer causality, prophylactic HPV vaccines have been effective in preventing (a) virus transmission and HPV infection, (b) benign HPV-induced tumors (genital warts), and (c) cervical intraepithelial neoplasia (CIN). Formal evidence of the prevention of cervical cancer by these HPV vaccines still awaits confirmation, and the same applies to the eventual prevention of human cancers at other anatomic sites, part of the global burden of oncogenic HPVs.