Discovery of human papillomavirus causing cervical cancer
Against the prevailing view during the 1970s, Harald zur Hausen postulated a role for human papilloma virus (HPV) in cervical cancer. He assumed that the tumour cells, if they contained an oncogenic virus, should harbour viral DNA integrated into their genomes. The HPV genes promoting cells proliferation should therefore be detectable by specifically searching tumour cells for such viral DNA. Harald zur Hausen pursued this idea for over 10 years by searching for different HPV types, a search made difficult by the fact that only parts of the viral DNA were integrated into the host genome.

Importance of the HPV discovery
The global public health burden attributable to HPVs is considerable. More than 5% of all cancers worldwide are caused by persistent infection with this virus. Infection by the HPV is the most common sexually transmitted agent, afflicting 50-80% of the population. Of the more than 100 HPV types known, about 40 infect the genital tract, and 15 of these put women at risk for cervical cancer. In addition, HPV is found in some vulval penile, oral and other cancers. HPV can be detected in 99,7% of women with histologically confirmed cervical cancer, affecting some 500,000 women per year.

Harald Zur Hausen demonstrated novel properties of HPV that have led to an understanding of mechanism for papilloma virus-induced carcinogenesis and the predisposing factors for viral persistence and cellular transformation. He found novel HPV-DNA in cervix cancer biopsies, and thus discovered the new, tumourigenic HPV16 type in 1983. In 1984, he cloned HPV16 and 18 from patients with cervical cancer. The HPV types 16 and 18 were consistently found in about 70% of cervical cancer biopsies throughout the world. Vaccines were ultimately developed that provide >= 95% protection from infection by the high risk HPV 16 and 18 types. The vaccines may also reduce the need for surgery and the global burden of cervical cancer.

From Nobelförsamlingen. The Nobel Assembly at Karolinska Institute