VANCOUVER – An analysis of cervical cancers in Ugandan women uncovers significant genomic differences between tumours caused by different strains of human papillomavirus (HPV), indicating that HPV type may impact cervical cancer characteristics and prognosis.
HPV infection is a leading cause of cervical cancer. In a study published August 3 in Nature Genetics, a team of researchers, including scientists at the University of British Columbia and Canada’s Michael Smith Genome Sciences Centre (GSC) at BC Cancer, compared cervical cancer samples infected by different evolutionary related groups of HPV types, known as clades, and identified previously unknown differences in how HPV clades impact the human genome. HPV-16 and HPV-18, belonging to clades A9 and A7, respectively, are the most common causes of cervical cancer detected in at least 70 per cent of cases. Although both are considered high-risk, HPV-18 was associated with more clinically aggressive cancers.
“We are very grateful to have had the opportunity to engage in a wonderful collaboration, involving teams of researchers from different countries and continents, to use genome science to analyze these very precious samples from Ugandan patients,” says Dr. Marco Marra, Director of the GSC and head of UBC’s department of medical genetics in the faculty of medicine. “This opportunity speaks to the foresight of those who collaborated with the Uganda Cancer Institute in Kampala to perform sample collection, and the study funders that made it possible. We are especially grateful to the support of the patients, without whom this work could not have happened.”
In B.C., cervical cancer incidence has been decreasing due to HPV vaccination and regular screening; however, cervical cancer is the fourth most common cancer worldwide and is the most common form of cancer-related mortality in sub-Saharan African women, with researchers predicting a 50 per cent increase in cervical cancer mortality by 2040. It is thus critically important to study cervical cancer in these populations, and to compare the results obtained to other HPV-associated cancers, such as head and neck cancers, which are being observed with increasing frequency in western populations.
“BC Cancer continues to be a leader in the global understanding of cancer,” says Dr. François Bénard, Vice President of Research at BC Cancer. “We are proud of the work of Dr. Marra and co-authors on this study, notably of the contribution of trainees. We are reminded that our research is not a purely academic exercise. Such work delivers a positive impact for everyone affected by cancer – in B.C. and beyond.”
The Frederick National Laboratory for Cancer Research, currently operated by Leidos Biomedical Research, Inc., subcontracted the GSC for sequencing and bioinformatic analysis, contributing approximately 95 per cent ($3,135,324) of the project’s funding. The remaining five per cent ($156,766) came from other nongovernment sources.
- Every year in B.C., approximately:
- 200 people will be diagnosed with cervical cancer.
- 50 will die from the disease.
- The HPV vaccine is provided free to girls and boys in Grade 6 as part of routine school vaccination programs.
- HPV is so common that the majority of sexually active women get the virus at some point in their lives.
- The World Health Organization recently announced that the elimination of cervical cancer is now one of its top priorities.
- HPV vaccination rates in low- and middle-income countries remain low. Limited resources and a high prevalence of HIV further complicates prevention and treatment strategies.