Key takeaways:
Is cancer a virus? The simple answer is no – cancer is not an infectious virus. It’s a disease that causes some of the body’s cells to grow uncontrollably and spread to other parts of the body.1
However, scientists have discovered that infectious agents contribute to 15–20% of human cancers worldwide.2 These agents are known as oncogenic viruses, or oncoviruses.2
Recognizing the link between viruses and cancers has reshaped cancer prevention and diagnosis.2 For example, widespread human papillomavirus (HPV) vaccination and screening is reducing cervical cancer rates, and hepatitis B virus (HBV) vaccination has reduced the chronic HBV infections linked to liver cancer.2 Diagnostics have also evolved to identify viral causes of tumors, which helps doctors tailor prevention and treatment strategies.2
While new molecular tests are emerging, immunoassays remain central at every step of the patient pathway for virus-linked cancers. From the early detection of viral infections3 to monitoring treatment,4 immunoassays provide actionable insights. Crucially, they often do so in ways that are more accessible and scalable than those of molecular assays.5
Rather than being replaced by genetic tests, immunoassays complement molecular diagnostics, ensuring that viral oncology is integrated into everyday clinical practice in a practical, cost-effective way. This is where trusted immunoassay material suppliers like Medix Biochemica can help.
Many common human viruses can set the stage for cancer as a result of years of chronic infection. Below, we highlight key virus–cancer connections and how diagnostics detect these viruses or their effects.
HPV is a common DNA virus transmitted by skin-to-skin and sexual contact.2,6 More than 600 million people globally have HPV.2 The virus can cause abnormal tissue growth (such as warts) and other changes to cells.7 It produces oncoproteins, which disrupt cell safeguards and can trigger malignant transformation of the affected tissue over time.6
High-risk strains of HPV are responsible for 99% of cervical cancer cases, as well as a significant proportion of cancers of the anus, penis, vagina, vulva and throat.2 In fact, HPV alone is responsible for an estimated 5% of all cancers worldwide when you combine these sites.2
Diagnostics for HPV
The cornerstone of cervical cancer screening today is HPV DNA testing, which detects high-risk HPV genetic material in cervical samples.7,8 These molecular tests are highly sensitive, finding the virus early. However, immunoassays play a pivotal role too. In pathology labs, immunohistochemistry (IHC) is used on biopsy specimens as a surrogate marker of HPV-driven cancer.9 Specifically, staining for the p16 protein (which accumulates in HPV-infected tumor cells) is widely recommended for head and neck tumors to confirm HPV involvement.9 The College of American Pathologists advises using p16 IHC on oropharyngeal cancers because it is affordable, fast and reliable in predicting HPV-positive status.9
Immunoassays are also used in HPV vaccine research and epidemiology to measure antibodies that act against HPV.10 In clinical practice, serological tests for HPV antibodies are not routine diagnostics for infection (since most people eventually clear HPV); however, emerging studies suggest that antibodies against HPV’s oncoproteins (like E6/E7) might serve as biomarkers for cancer risk and recurrence monitoring.11
| HPV diagnostics summary HPV diagnostics combine molecular tests (to directly detect the virus’s DNA or RNA)7,8 with immunoassays (to detect viral proteins or their downstream effects in tissues).9 This dual approach improves early detection of HPV-driven precancers and ensures that patients with HPV-associated tumors get appropriate, targeted treatment. |
EBV (also known as human herpesvirus-4) is another common virus, carried by about 90–95% of adults worldwide.2,12 EBV is often asymptomatic and may sometimes cause mild mononucleosis (‘mono’) infections,12 but it can persist for life and is also linked to several malignancies.2,12 These include Burkitt’s lymphoma, Hodgkin’s lymphoma, and nasopharyngeal carcinoma (NPC) in particular.2 The virus’s ability to infect B-cells and epithelial cells, and then ‘hide’ in a latent state, contributes to oncogenesis years later in a minority of infected people, such as immunocompromised patients.2
Diagnostics for EBV
A variety of tests help detect EBV infection and EBV-related cancers.
In the blood, serologic antibody panels are the primary tools to determine EBV status.13 Doctors measure antibodies such as viral capsid antigen (VCA) immunoglobin M/immunoglobin G and EBV nuclear antigen (EBNA) immunoglobin G.13 Elevated titers of certain EBV antibodies are used in some endemic regions to screen for NPC risk.13,14 These immunoassays alert clinicians, even before symptoms arise, to patients who might have an early-stage NPC tumor.13,14
In confirmed cancers, tumor tissue testing is also important. Pathologists often perform EBV-encoded RNA in situ hybridization (EBER-ISH) or IHC for latent viral proteins on biopsy samples, to see if a tumor is EBV-positive.15,16 For example, in Hodgkin’s lymphoma, finding EBV protein expression in the malignant cells can confirm the virus’s involvement. Up to 40% of Hodgkin’s lymphoma cases are associated with EBV.17
Similarly, virtually all NPCs are associated with EBV,18 and labs can detect EBV DNA or antigens in tumor tissue.19 Immunohistochemical staining can reveal EBV’s latent proteins within tumor cells, helping to diagnose EBV-driven malignancy.
| EBV diagnostics in summary Antibody immunoassays (for EBV infection in blood) and IHC (for EBV markers in tumor tissue) work together to identify the virus’s involvement.13-16 This guides patient management; for example, EBV-positive NPC patients are often monitored with EBV DNA or antibody levels during and after therapy to gauge recurrence risk.15,16 |
HBV and HCV are oncoviruses that chronically infect the liver.20 Chronic HBV or HCV infection can lead to cirrhosis and eventually hepatocellular carcinoma (HCC) – the primary form of liver cancer.2,20 Worldwide, over half of HCC cases are attributable to HBV infection, and about 15–25% are due to HCV.2
Diagnostics for HBV/HCV
Public health programs have long relied on immunoassay-based tests as the gold standard for screening hepatitis viruses.
For HBV, the key marker is hepatitis B surface antigen (HBsAg) in the blood; its presence confirms an active HBV infection.21
For HCV, the first-line test is an anti-HCV antibody screen.22 According to World Health Organization (WHO) recommendations, detection of HCV antibodies by enzyme immunoassay (EIA) is the trusted initial screening method.22 A positive HCV antibody test is then confirmed with an HCV RNA polymerase chain reaction (PCR) test to verify active infection.22 In other words, an immunoassay identifies the exposure, and a molecular test confirms the virus is currently replicating.22
These immunoassays are highly accessible and can be run on automated lab platforms or as rapid point-of-care (PoC) tests.23 For example, rapid test kits are available to detect HBsAg or HCV antibodies with a finger-prick of blood, which is extremely useful in resource-limited settings.23 HBsAg is often the earliest indicator of HBV infection and can appear even before symptoms,22 so this PoC testing allows for early intervention.
In clinical practice, if a patient has a liver tumor, testing their blood for HBsAg and HCV antibodies is standard to see if a hepatitis virus is involved.24 Even after a cancer diagnosis, continuing to monitor viral markers is important. For example, in an HBV-positive liver cancer patient, doctors will track HBV DNA levels (by PCR) and may also measure HBV antigens or liver enzymes via immunoassays to guide antiviral therapy during cancer treatment.
| HBV/HCV diagnostics in summary Serological immunoassays for HBV and HCV are indispensable; they are widely used for hepatitis screening, helping determine who needs further genomic testing or preventive treatment.22 This wide reach is important for reducing virus-driven liver cancers through the early detection and treatment of hepatitis. |
HTLV-1 is a sexually transmitted infection and retrovirus that affects an estimated 5–10 million people worldwide.2 In about 5% of infected people, HTLV-1 can cause a malignant disease called adult T-cell leukemia/lymphoma (ATLL), an aggressive T-cell cancer with poor prognosis.2
HHV-8, also known as Kaposi’s sarcoma-associated herpesvirus (KSHV), is the cause of Kaposi’s sarcoma, a cancer of the blood vessel linings.2 HHV-8 is also a major cause of HIV/AIDS-related cancer.2
Diagnostics for HTLV-1 and HHV-8
Diagnosing HTLV-1 infection relies on blood tests. An enzyme-linked immunoassay (ELISA) screening assay for HTLV-1/2 antibodies is typically used, followed by a confirmatory Western blot or immunoblot to differentiate the virus type.25 In an HTLV-positive patient suspected of ATLL, finding antibodies to HTLV-1 supports the diagnosis (along with clinical findings).25 Additionally, PCR tests can detect HTLV-1 proviral DNA in blood or tissues.26 These tests are usually done after an immunoassay flags the infection.26
Diagnostics for HHV-8 are often tied to pathology. The most direct way to confirm Kaposi’s sarcoma is by biopsy and immunohistochemical staining for HHV-8 latent nuclear antigen (LNA-1) in the tumor.27 This kind of immunoassay in tissue is now routine to distinguish Kaposi’s sarcoma from other spindle-cell tumors.27 Blood tests for HHV-8 are not commonly used for screening the general public. Instead, a patient presenting with suspicious lesions might get an HIV test and a biopsy28 with HHV-8 IHC.
| HTLV-1 and HHV-8 diagnostics in summary Serological immunoassays are the frontline for HTLV-1 detection.25 There is no vaccine or cure for HTLV-1 yet, so identifying carriers via testing is key to preventing the spread of the virus.26 |
Immunoassays are critical for confirming HHV-8 in tumors, and serology can support the diagnosis or evaluate exposure in at-risk groups.27,28 Together, these tests help ensure that virus-associated lesions are correctly identified and managed.
Despite the availability of sophisticated genetic tests, immunoassays remain indispensable in oncovirus/viral cancer diagnostics. Here’s why:
Accessible and scalable testing: Immunoassays are generally cost-effective and easy to deploy.29 In the context of viral cancers, immunoassays enable early detection programs to reach millions of people. These assays can often be automated for high-throughput testing or scaled down into PoC test kits, giving them unmatched reach.
Critical clinical insights (beyond genetics): Immunoassays provide information that complements molecular diagnostics. They can measure protein markers, antibodies and antigens,30 reflecting the patient’s immune response or the presence of viral proteins. Immunoassays often provide actionable insights which are crucial for personalized care.31
Complementing, not competing: The best diagnostic strategies combine both immunoassays and molecular testing to cover each other’s limitations. Molecular tests excel at detecting the genetic material of viruses or mutations, but they can fail if the virus is latent or present at low levels. Immunoassays can fill that gap.
Looking ahead, the ideal approach to cancer-causing viruses will integrate the strengths of immunoassays with the power of genomics and other innovations. Key developments on the horizon include:
Is cancer a virus?
No, cancer is a disease that causes some of the body’s cells to grow uncontrollably and spread to other parts of the body.1
Can a virus cause cancer?
Yes, certain viruses can cause cancer, particularly after long-term infection.2
Which viruses are linked to cancer?
Human papillomavirus (HPV), Epstein–Barr virus (EBV), hepatitis B and C viruses (HBV and HCV), human T-cell lymphotropic virus type 1 (HTLV-1) and human herpesvirus 8 (HHV-8) are all oncoviruses linked to different types of cancers.2
What role do immunoassays play in detecting oncoviruses?
A simple immunoassay can mean catching a cancer early, when it’s most curable. For someone already fighting cancer, immunoassays can guide personalized therapy, identifying virus-related factors that make certain treatments more effective. And after treatment, these assays help monitor for recurrence or viral reactivation, giving peace of mind that if cancer returns, it won’t go unseen.
By providing quick, reliable and widely available results, immunoassays ensure that advances in viral cancer knowledge translate to improved patient outcomes.
Medix Biochemica has more than 40 years of experience in producing premium-quality monoclonal antibodies for tumor marker detection, as well as extensive experience with purified cancer antigens for use in quality-control materials. Our optimized production methods, certified batch-to-batch consistency and expert customer service have made us one of the most important antibody suppliers for the in vitro diagnostics community.32
Download Medix Biochemica’s Tumor Markers Catalog to see our full selection of antibodies and biospecimens for use in cancer-detection immunoassays
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