Virus and Bacteria: Potential Risk Factors for Cancer

It’s crucial to remember that although cancer is not infectious like a common cold, some divergent viruses and bacterias are thought to influence the development of cancer.

Viruses are minute organisms undetectable by the naked eye, so much so that an ordinary microscope can hardly see them. They are genes in the form of DNA or RNA surrounded by a protein coating. For a virus to reproduce, it must infiltrate a living cell and hijack its core. When the DNA and RNA affect the host’s genes, it can urge the cells to mutate into virulent organisms.

In general, each type of virus tends to infect only a particular kind of cell in the body. For example, the viruses that cause a urinary tract infection only attack cells around the urinary system, while the virus associated with the common cold only go for cells lining the nose and throat.

Vaccines that Counter Cancer

Many types of viruses link with cancer in humans. Our increasing knowledge about viruses and its role in cancer has led to the development of vaccines that help prevent certain types of chronic diseases. But these vaccines can only do as much as protect against infections, and are ineffective once given to a person exposed to cancer-promoting viruses.

Common viruses associated with the development of cancer are:

Human Papilloma Viruses (HPVs)

More than 150 types of viruses are related to HPV. Papillomas are commonly known as warts which grow on the surface of the skin, but other warts are more malignant and could develop in mucous membranes such as the mouth, throat, or reproductive organ.

The simplest touch spreads HPV, and more than 40 types of it can be passed on through sexual contact.

A few types of HPV are the leading causes of cervical cancer, which is the second most common type of cancer among women worldwide. The development and availability of a Pap smear test, the screening procedure for cervical cancer, has decreased the number of cervical cancer patients in the United States. Not all women diagnosed with HPV will develop cervical cancer. Even though doctors can test women for HPV, there is no treatment for the disease itself. A Pap smear only shows precancerous changes in cells, but they can be destroyed or removed to stop cancer from developing.

Epstein-Barr Virus (EBV)

EBV, also known as human herpesvirus 4, is a member of the herpes virus family. It is one of the most common human viruses found all over the world. Most people get infected with EBV at some point in their lives. It spreads most commonly through bodily fluids — from coughing and sneezing to sharing drinks and utensils. However, EBV can also spread through sexual contact, blood transfusions, and organ transplantations. It can cause infectious mononucleosis and other illnesses.

Like other herpesvirus infections, EBV infection is constant. EBV infects and stays in white blood cells in the body called B lymphocytes. There are no medicines or treatments that promote the eradication of EBV, nor are there vaccines to help prevent it, but an EBV infection doesn’t cause serious problems in most people.

EBV infection increases a person’s risk of getting certain types of fast-growing lymphomas such as Burkitt lymphoma, Hodgkin lymphoma, and some cases of stomach cancer. EBV-related cancers are common in Africa and parts of Southeast Asia. Overall, very few people infected with EBV will ever develop cancer.

Human immunodeficiency virus (HIV)

HIV is the virus that causes acquired immune deficiency syndrome (AIDS). It highly increases a person’s risk of getting several types of cancer. It spreads through sexual contact — vaginal fluids, semen, blood, and breast milk from an infected person.

HIV infects and destroys white blood cells known as helper T-cells, which weakens the body’s immune system. This process allows some viruses, such as HPV, thrive, and opens the doorway for cancer to conquer.

People with HIV can develop diseases such as anal cancer, lung cancer, skin cancer, liver cancer, and Hodgkin’s disease.

Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV)

Both HBV and HCV cause liver infections. People with the virus may develop a chronic infection that can lead to cirrhosis, and the damage it results increases the risk of liver cancer.

HBV and HCV spread the same way HIV does — through sharing needles, having unprotected sex, or childbirth. They are also passed on through blood transfusions, but this is rare in the United States since donated blood is tested for viruses.

HCV is less likely to cause symptoms than HBV, but it is more liable to cause chronic infections that can lead to liver damage and cancer. HBV, on the other hand, is more likely to result in symptoms such as flu-like illnesses and jaundice. Adults usually recover from HBV infection within a span of a few months. Only a small percentage of adults go on to have chronic HBV infections, but this risk is higher in children. People with chronic HBV infections have an increased risk for liver cancer.

Treatment and preventive measures slow down liver damage and reduce the risk of cancer. The specific drugs can treat both hepatitis B and C infections. Although drugs for treating chronic hepatitis B exist, they do not cure the disease. They can only lower the risk of liver damage and help reduce the possibility of liver cancer developing.

Human T-Lymphotropic Virus-1 (HTLV-1)

This virus is considered an oncovirus cause of lymphoproliferative diseases such as adult T cell leukemia or lymphoma (ATL) and disturbs the immune responses, which results in HTLV-I associated myelopathy (HAM) or tropical spastic paraparesis (TSP).

HTLV-1 belongs to a class of viruses called retroviruses. These viruses use RNA for their genetic code. To reproduce, they must change their RNA genes into DNA. Some of the new DNA genes can become part of the chromosomes of the cell infiltrated by the virus. This process can change how the cell grows and divides, often leading to cancer.

HTLV-1 spreads the same way as HIV. Infected mothers can also pass on the virus to their children, although this risk decreases if the mother omits to breastfeed.

The bottom line: Viruses and bacteria can wander into the body’s territories, divide, and conquer. As always, early diagnosis and prevention is key to defeating cancer-causing properties.