HPV (human papillomavirus) is the most common sexually transmitted infection in the United States. There are over 40 types of HPV,1 some of which cause genital warts and some of which cause cancer.
About 26,000 cases of cancer in the U.S. are attributed to HPV each year; about 17,000 in women and 9,000 in men. From 2004—2008, practically every case of cervical cancer was found to be caused by HPV,2, as well as 90% of anal cancers, 65% of vaginal cancers, and 50% of vulvar cancers.
Vaccinations have proven to be an effective countermeasure to HPV and are successful in preventing the spread of the virus. Before scientists can undertake an immunization project, however, they need to assess the relative risk of HPV infection for different parts of the world. Recently, some concerns have surfaced over the effectiveness of HPV assays, indicating that they may be missing some cases of actual HPV infection. Accurately measuring the prevalence of HPV is important for creating appropriate vaccination programs, as well as understanding how successful they have been.
A recent study published in Diagnostic Molecular Pathology3 tested the effectiveness of two types of HPV assays. The HPV data came from women who submitted samples for a National HPV Immunization Exercise, totaling 2142 samples. A traditional line-blot assay was compared to a more recently developed multiplex assay.
The traditional assay was a reverse hybridization HPV genotyping assay, provided by Digene. This assay tested for 18 different types of HPV. The research multiplex HPV genotype assay used Luminex® xMAP® Technology4 to test for 24 different strains of HPV. This test is not available for diagnostic use, and was not utilized for diagnostic purposes during this study.
Luminex’s xMAP Technology is a leader in multiplexing technology, and it allows scientists to test for multiple different proteins or nucleic acids simultaneously, drastically speeding up the assay process.
The multiplex assay run on Luminex Technology detected a higher prevalence of HPV among these de-identified samples than the traditional test, for every type of sample used:
- The multiplex assay detected HPV in 51% of samples versus 43.8% for the traditional assay.
- When it came to cervical samples prepared with liquid-based cytography (LBC), the success rates were 56% (multiplex) to 47.6% (traditional).
- For urine samples, it was 35.3% (multiplex) versus 32.3% (traditional).
- For self-taken swabs, it was 46.9% (multiplex) versus 39.9% (traditional).
Not only did the Luminex-based multiplex test detect more types of HPV than the traditional assay—accounting for some of the difference between multiplex assays and traditional tests detecting HPV, it also found more cases of the virus when it was matched for the types that both assays had in common. This research shows that multiplexing technology may be used as a successful method for accurately detecting the types of HPV virus. The authors recommend that the method of assessing the prevalence of HPV should be thoughtfully taken into account, in order to provide healthcare workers better information about the HPV situation and letting them create more effective vaccination programs. The clinical importance of the additional strains that may be detected using multiplex technology require further study.
References
- Reducing the burden of HPV-associated cancer and disease through vaccination in the US. Center for Disease Control and Prevention (Internet). Cited 2013 December. Available from: http://www.cdc.gov/about/grand-rounds/archives/2013/February2013.htm
- HPV-associated cancers statistics. Center for Disease Control and Prevention (Internet). Cited 2013 December. Available from: http://www.cdc.gov/cancer/hpv/statistics/
- Effect of HPV assay choice on perceived prevalence in a population-based sample. Diagn Mol Pathol. 2013 Jun;22(2):85-90.
- https://lmnxja.acscreativedev.com/xmap-technology/