{"id":634537,"date":"2026-10-18T18:34:18","date_gmt":"2026-10-18T18:34:18","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/634537\/"},"modified":"2026-10-18T18:34:18","modified_gmt":"2026-10-18T18:34:18","slug":"nearly-1-in-8-cancers-worldwide-are-caused-by-infections-many-could-be-prevented","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/634537\/","title":{"rendered":"Nearly 1 in 8 cancers worldwide are caused by infections. Many could be prevented"},"content":{"rendered":"

\"-3\"<\/a>Image credits: National Institute of Allergy and Infectious Diseases.<\/p>\n

Around 12% of the world\u2019s total cancer cases in 2024 were likely caused by an infection, according to new research<\/a> from the World Health Organization (WHO).<\/p>\n

The study, published today in The Lancet Oncology, analysed the frequency and causes of different cancers, specifically examining the role of infections.<\/p>\n

It linked 2.3 million new cancer cases to an infection. Most were caused by just five pathogens: Helicobacter pylori (4%), human papillomavirus, or HPV (4%), hepatitis B (2%), Epstein-Barr virus (1%) and hepatitis C (under 1%). These infections can cause more than 20 different types of cancer, including stomach, liver, blood and cervical cancers.<\/p>\n

So, how can an infection cause cancer? And does this mean these cancers are preventable?<\/p>\n

Did we already know about this link?<\/p>\n

Some of the study authors have been researching this field for around thirty years. Their previous work investigated cancer cases caused by infections in 1990<\/a>, 2002<\/a>, 2008<\/a>, 2012<\/a>, and 2018<\/a>.<\/p>\n

The proportion of cancer cases caused by infections may appear to have dropped during those years (from a high of 18% in 2002), but the authors stress these comparisons cannot really be made confidently, as the sources and quality of the data have changed over time.<\/p>\n

In fact, the latest study wasn\u2019t trying to compare between the years. Instead, it aims to highlight where controlling and preventing infections can help to reduce cancer rates.<\/p>\n

To make sense of this, it helps to know how infection is linked to cancer. Extensive research<\/a> has dissected the molecular mechanisms behind this link, and we now know there are various ways infections can cause cancer.<\/p>\n

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How can a virus cause cancer?<\/p>\n

\"\" <\/a>Image via Unsplash.<\/p>\n

A virus can (directly or indirectly) change the genes of the cell it infects (the host cell), making that cell more likely to grow out of control and eventually become a cancer.<\/p>\n

There are three main ways<\/a> viruses can do this.<\/p>\n

The first is by turning off the ability of a cell to destroy itself (for example, by inactivating the TP53 protein) or to stop dividing (for example, by inactivating the RB protein). A healthy cell would normally try to do these things if infected by a virus.<\/p>\n

The second way a virus can cause cancer is by inserting its own DNA into the host cell\u2019s DNA, which can accidentally disrupt genes that control cell death or division (like those above).<\/p>\n

The third way is when the virus itself carries a gene that causes cancer (an oncogene). In many cases, the virus has picked up these by accident from another organism<\/a>.<\/p>\n

The link between viruses and cancer is actually foundational to modern cancer science<\/a>, and has helped scientists uncover the direct link between genetics and cancer<\/a> we now take for granted.<\/p>\n

What about bacteria and parasites?<\/p>\n

\"\"<\/a><\/p>\n

It\u2019s not just viruses that cause cancer. Infections from bacteria or parasites \u2013 such as Helicobacter pylori<\/a> (best known for causing stomach ulcers), or Opisthorchis viverrini<\/a> (a liver fluke, a type of parasitic worm) \u2013 can also lead to cancer.<\/p>\n

However, these work more indirectly than viruses. Long-term (chronic) infection by these types of organisms can cause significant stress to different tissues.<\/p>\n

Inflammation<\/a>, normally a part of the body\u2019s immune response, can then become overactive, damaging the tissues further.<\/p>\n

These stresses can result in cancer-causing DNA damage in cells, or lead to mistakes during cell division as the body tries to rapidly produce new cells to repair tissue damage.<\/p>\n

In both cases, the cells acquire genetic mutations that put them on the road towards becoming cancer.<\/p>\n

Many cancers are preventable<\/p>\n

Of course, there may be other mechanisms linking infections and cancer that we don\u2019t know about but, overall, the connection between infections and cancer is indisputable.<\/p>\n

Critically, what this tells us \u2013 and what this new study into the rates of cancers caused by infections reinforces \u2013 is that many cancers are preventable.<\/p>\n

In Australia, one of the best examples of preventing cancers caused by infections is the human papillomavirus (HPV) vaccine.<\/p>\n

This vaccine protects against certain strains of HPV strongly associated with cervical cancer<\/a>, and is available to adolescents in Australia.<\/p>\n

Since the program began in 2007, HPV infections dropped by 90%<\/a> among people eligible to receive the vaccine.<\/p>\n

Because of its success, Australia could be on track to eliminate cervical cancer by 2035<\/a>.<\/p>\n

However, vaccination rates among 15-year-olds have fallen from 85.7% in 2020 to 79.5% in 2024<\/a>, which is concerning. As is the case for all vaccines, a high proportion of the population need to be vaccinated<\/a> to also protect those who, for health reasons, cannot be vaccinated. For HPV, the WHO and Australian target is to vaccinate 90% of 15-year-old girls<\/a> by 2030.<\/p>\n

Sadly, the new study also highlights<\/a> that around 75% of cancers caused by infections were found in low- and middle-income countries.<\/p>\n

Treating infections that can lead to cancer \u2013 such as HIV, H. pylori, and hepatitis B and C \u2013 is one way to reduce cancer rates. Preventative measures also play a major role, including vaccinations, condoms and disease screening.<\/p>\n

However, the availability of these programs in poorer countries can be limited, and so access continues to be a major equity issue in combating cancer.<\/p>\n

The authors would like to acknowledge the contribution of Amali Cooray from the Olivia Newton-John Cancer Research Institute to this article.<\/p>\n

John (Eddie) La Marca<\/a>, Senior Research Officer, Blood Cells and Blood Cancer, WEHI (Walter and Eliza Hall Institute of Medical Research)<\/a> and Sarah Diepstraten<\/a>, Senior Research Officer, Blood Cells and Blood Cancer Division, WEHI (Walter and Eliza Hall Institute of Medical Research)<\/a><\/p>\n

This article is republished from The Conversation<\/a> under a Creative Commons license. Read the original article<\/a>.<\/p>\n


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