Catch Cancer Facts -- Yes You Can!

This was a letter to the editor in response to a column by Dr. Andy Ho in the Straits Times. After it was published, it was pointed out, to my horror, that part of my letter could be interpreted to mean that only sexually promiscuous women get cervical cancer. So in my attempt to correct one misconception, I propagated another. Ah, pride does indeed go before a fall. The version below corrects and extends the letter.

There were other reactions to Ho's article, and reasoned responses to my letter from Dr. Yik Keng Yeong and angry doc, which you can find here and here.

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It takes long and patient striving to eliminate medical myths from the popular imagination. It is therefore dismaying that Mr. Andy Ho’s recent column (“Catch” cancer? Yes, you can) will have set back efforts to educate the public on the (non)infectivity of cancer.

Mr. Ho makes only the briefest of references to the core truth, which is that cancer itself is not contagious -- only the viruses that can help to provoke certain cancers. A number of key facts are then lost, overshadowed or misunderstood in the remainder of the article. Here is some of the crucial information missing from Mr. Ho’s column.

1. Very few types of cancers involve a virus. Mr. Ho mentions almost all of them. There are far more types of cancers that, to the best of our knowledge, have no viral or contagious involvement whatsoever.

2. With infections by cancer-facilitating viruses, it is always a minority of infections that result in cancer.

3. Many such cancer-causing viruses act very early in the development of cancer, and infectious virus may not even be detectable once the cancer is full blown, often years later.

4. Though certain strains of human papilloma virus (HPV) most definitely provoke cervical cancer, the cervical cancer cells themselves do NOT produce any virus. This is because the virus inactivates itself from the earliest steps in cancer progression. Therefore, cervical cancer is NOT infectious. Any woman can contract HPV and get cervical cancer, regardless of lifestyle. However, the greatest risk factor for cervical cancer is multiple sexual partners as this increases the probability of developing the sustained HPV infections that provoke the cancer. So a woman can decrease her risk of cervical cancer by limiting her sexual partners. But she will gain nothing by avoiding the company of someone who has the disease already for the simple reason that there is no risk in the first place.

5. Epstein-Barr virus (EBV) infections can, in a small percentage of cases, lead to the blood cancers noted by Mr. Ho. However, the development of Burkitt’s lymphoma requires that the patient have malaria at the same time as the EBV infection, something that most of us need not worry about. More importantly, EBV is an extremely common and widespread virus. Most of us have already been infected with EBV. In the United States, 95% of adults have had EBV infections. Therefore, if you haven’t had it already, your chances of contracting EBV are more likely to occur on an MRT train than in a cancer ward. Thus, the hospital dietitian was absolutely correct to say that there was no danger in sharing a meal with a patient with Hodgkin’s lymphoma (another cancer whose onset has been linked to EBV infection).

6. Kaposi’s sarcoma is a cancer that has been linked to infection with human herpesvirus 8 (HHV-8) in AIDS patients. I repeat, in AIDS patients. In other words, Kaposi’s sarcoma only arises in patients that have greatly debilitated immune systems. HHV-8 is widespread in some regions of the world without adverse effects. Promiscuous sexual activity increases the risk of contracting HHV-8, so the danger is not hanging out with AIDS patients, but rather lifestyle considerations. If you are infected, you will not be at any risk of developing the sarcoma if you are any where near to reasonably good health.

7. Mr. Ho’s statement that close to one in five cancers is caused by a virus is grossly misleading. The most frequent cancer types in Singapore (breast, colorectum, lung, prostate, ovary) have no viral component whatsoever. A proportion of some other cancers, such as liver and stomach, MAY involve an infection, but here the problem is not the virus (or bacteria), but rather the chronic state of inflammation associated with hepatitis and ulcers. Once again, hepatitis can be picked up in a food court. That’s why we get vaccinated. Cancer patients are not the problem.

From a biological point of view, the mechanisms by which some viruses facilitate cancer formation are fascinating, and provide valuable insights into the ways that cancer arises in uninfected individuals -- the vast majority of cases.

From a clinical perspective, viral involvement in cancer is restricted to a select minority of well-recognized cancers. Not one of these can cause a person to “catch” cancer in any meaningful use of the term.

If Mr. Ho’s article were to prevent a family member or friend from hugging or kissing a cancer patient, it would be a tragedy, since the chances of contracting cancer from the patient, in either the near or long term, are zero.


Mark Featherstone
Professor and lecturer in cancer biology
School of Biological Sciences
Nanyang Technological University