In this interview, Professor Harald zur Hausen, recipient of the SGM Medal prize, recounts his groundbreaking research that established the causal link between Human Papillomavirus (HPV) and cervical cancer. He details his scientific journey, beginning with an early interest in the connection between infections and cancer, which led him to investigate cervical cancer. After disproving the prevailing theory of a link to Herpes Simplex Virus, he pursued a hypothesis involving papillomaviruses, inspired by rare cases of malignant genital warts. The conversation covers the challenging process that led to the discovery of HPV-16 and HPV-18, the primary oncogenic types. Professor zur Hausen explains that viral carcinogenesis is a biological "accident" for both the virus and the host. He also discusses his current research into potential infectious links to colon cancer and childhood leukemia, and shares his perspective on the life-saving HPV vaccine, advocating for its safety, wider adoption, and the importance of vaccinating boys to combat transmission and prevent other cancers.
Professor Harald zur Hausen on Uncovering the Link Between HPV and Cancer
0:00:25 Early Inspiration: Professor zur Hausen's interest in the link between infections and cancer began during his medical studies, inspired by how bacteriophages (viruses that infect bacteria) can persist in their hosts.
0:02:24 The Cervical Cancer Puzzle: He notes that the first epidemiological suggestion that cervical cancer could be caused by a sexually transmitted agent dates back to 1842.
0:03:09 A Shift in Focus: After his team's work disproved the then-popular theory linking Herpes Simplex Virus type 2 to cervical cancer, he turned his attention to papillomaviruses, the cause of human warts, after reading about rare instances of genital warts becoming malignant.
0:04:40 The Breakthrough Discovery: After a long and difficult period, his team isolated HPV DNA from genital warts. While this type wasn't found in cancer cells, it was used as a probe that detected faint signals of related, but different, viruses in tumor samples. This crucial step led to the identification of HPV-16 and HPV-18.
0:05:47 The Oncogenic Types: The discovery was a turning point, revealing that HPV-16 was present in about 50% of cervical cancers and HPV-18 in about 20%. Today, we know of 178 characterized HPV types, but only about 13-15 are linked to cancer.
0:08:00 Cancer as a Biological "Accident": Professor zur Hausen explains that for the virus, causing cancer is a dead end. The viral DNA found in tumors is often mutated or partially deleted, rendering the virus unable to replicate. The cancer is an accident for both the virus and the host cell.
0:08:47 Exploring Other Virus-Cancer Links: He is currently investigating potential infectious causes for other cancers, including a link between agents transmitted from cattle (via red meat consumption) and colon cancer, as well as a potential prenatal infection leading to childhood leukemias.
0:09:42 On the HPV Vaccine: He expresses satisfaction that his work led to a life-saving vaccine but emphasizes humility over pride, noting how many scientific questions remain. He stresses the vaccine's importance as cervical cancer is the second most frequent cancer in women globally.
0:11:34 Combating Vaccine Hesitancy: Professor zur Hausen is disturbed by the trend of vaccine refusal, highlighting that studies show the HPV vaccine is extremely safe (e.g., one allergic reaction per 100,000 vaccinees in Australian studies).
0:12:12 Advocating for Vaccinating Boys: He strongly advocates for vaccinating boys, as they are effective transmitters of the virus and are also susceptible to HPV-linked cancers of the oropharyngeal and anal regions.