What causes Cancer?

Overall, cancer occurs due to random damage to our genes. A little bit of random damage to our genes occurs over someone’s lifetime, ending up in a new growth, known as neoplasm (neo-, new; plasm-growth). It is a progressive disease meaning that a person may be diagnosed with cancer today, but the process of genetic change will have been going on for many years.

 Now, how does this genetic damage occur? In brief, the causes of the damage can be grouped into three major categories:

Sometimes there may be no reason as to why people get some types of cancers…they just do! For example, we do not really know what might cause brain tumors. It might just be a random damage that occurs when cells are reproducing or replicating; something just goes wrong in this process mistake occurs (In scientific terms copying and transcribing of cell DNA goes wrong). So sometimes these mistakes can be repaired, or if not, the damaged cell will just die (programmed cell death called ‘apoptosis’). But sometimes the mistakes are not repaired, and it allows the cell to continue the replication process in a damaged form. This damage is taken into the next cell, then more damage is done, then more, then more…. 

Such a process might explain why some types of cancers occur. And such spontaneous damage might also be further exacerbated by other types of damage.

Sometimes one can get cancer as a result of exposure to carcinogens or cancer causing agents’ (or at least potentially cancer causing) and these include.

• Environmental; things in our external environment that might be cancer-causing, and we have very little control over them. For example, breathing in car exhaust fumes as a result of air pollution cooking with wood, fuels, roofing material, and sometimes exposure during the work someone does such as mining work, working in the pesticides industry, radiation work, etc. There is little we can do about these exposures individually, so we expect our government to help us out here with appropriate legalization, policies, and protection measures.

•  Lifestyle factors: Sometimes cancer can be self-induced (associated with the choices of our lifestyle behaviors), for example, deciding to smoke, taking alcohol, the foods we eat, having a sedentary lifestyle, and weight gain; all these put us at risk of getting cancer. We can limit our risk of getting cancer by reducing our exposure to carcinogens with appropriate lifestyle choices.

•  Infections: Also, in Uganda, about 28.7% of cancers are due to infectious agents. The main types of infections attributed to cancer are;

1. human papillomavirus (HPV) is responsible for 70-80% of cancer of the cervix (the most common cancer in Uganda) and other cancers like anal, genital and oral-pharynx cancers. HPV is a majorly sexually transmitted infection.

2. Hepatitis B/C associated with 85% of liver cancer;

3. Helicobacter Pylori accounts for 80% of the stomach cancers; and

4. other viruses like HIV are associated with an increased risk of cancer overall. HIV is a major sexually transmitted infection.

In some cases, the damage to the cells may have been already done genetically, the reason some people inherit damaged genes (BRCA gene, APC gene) which will predispose them to certain types of cancers. Again, there is very little we can do about this, other than manage the situation as it arises.

 Anyway, irrespective of the cause of the damage, it is damage nonetheless, that happens over a long period; Little bits of damage over a lifetime.