DNA test could improve access to cervical screening

A DNA test for HPV infections could broaden access to cervical cancer screening, scientists have found.

Bioengineers from Rice University, Texas have shown that a low-cost, point-of-care DNA test for HPV could make cervical cancer screening more accessible in low and middle-income countries, where 90 per cent of deaths from cervical cancer occur.

HPV is a common virus spread by skin-to-skin contact. It is estimated that around eight in 10 people get it during their lifetime.

There are more than 200 types of HPV – around 40 types affect the anus and genitals and 14 of these are linked to some cancers.

Cervical cancer is the most common HPV-associated cancer. It kills more than 300,000 women globally every year, disproportionately affecting women in low- and middle-income countries such as South Africa, India, China and Brazil.

‘A mobile diagnostic van’

Researchers at Rice University, led by Professor Rebecca Richards-Kortum, spent more than two years developing a DNA testing platform to simplify the equipment needs and procedures for testing.

In a study, published in Science Translational Medicine, Richards-Kortum’s team and co-authors from the National Cancer Institute, the Mozambique Ministry of Health, Baylor College of Medicine and the University of Texas MD Anderson Cancer Center showed the platform could produce clinically relevant results on samples collected at both US clinical sites and at clinical field sites in Mozambique.

They demonstrated their six-step test for two high-risk types of HPV delivered results in 45 minutes and required just two pieces of equipment. One is a small centrifugee and the other is a purpose-built, dual-chamber heater called NATflow which allowed the researchers to use disposable cartridges to avoid false positives arising from workspace contamination.

Kathryn Kundrod, study first author and cancer prevention fellow at the National Cancer Institute, said: “We know what we need to do to prevent cervical cancer. It’s really a matter of access at this point, and that’s one reason this study is exciting from a global health perspective.

“It demonstrates a testing process that could potentially be combined with point-of-care diagnostic and treatment technologies to allow women who’ve never had access to be screened and treated in a single visit in settings like a small clinic or a mobile diagnostic van.”

Richards-Kortum, Rice’s Malcolm Gillis University Professor, professor of bioengineering and the founding director of the Rice360 Institute for Global Health Technologies, said: “The vast majority of disease detected through screening is precancerous, before the point at which people have cancer.

“That’s why screening programmes are so effective. People who are routinely screened very rarely progress to cervical cancer. It’s people who have never been screened in their lives, or who get screened on really infrequent intervals, who are really at risk.

“That’s why it’s so critical to address the disparities that exist and think about new ways to deliver screening, diagnosis and treatment.”

Kundrod said that if both the NATflow platform and test cartridges were produced on a large scale, each dual-chamber heater would cost an estimated US$500 and each test less than US$5.

She added: “The platform is the other thing that makes this exciting, because it can easily be adapted for DNA tests for other diseases.

“Preventing contamination has been a huge problem for DNA-based point-of-care tests. This is one of the first platforms to address that, and so far it’s the only one to solve that in a way where all the pieces can be easily manufactured with injection molding, which is important from a cost perspective.”

However, Kundrod said the team’s HPV test won’t be ready for widespread use until researchers modify it to detect more cancer-causing types of HPV and conduct additional clinical tests, adding that studies have consistently shown that HPV screening is the most effective way to prevent cervical cancer while DNA testing is the most effective way to screen for HPV infections.