Environmental Carcinogens and Cancer Progression: A harmful association

Environmental Carcinogens and Cancer Progression: A harmful association

Talking about environmental carcinogens, it involves all the indoor and outdoor air pollutants along with drinking water and soil contaminants. The association between environmental pollution and human health is very disturbing as the pollutants may lead to substantial health concerns, specifically to those body parts which extremely exposed to these hazard components.

These pollutants can adversely impact human health and can alter the psychological factors and even genetic makeup. Asthma and allergies are the two most significant problems linked to these pollutants. However, except these concerns, there is one more concern that has not been enlightened in this context yet. That health concern is cancer.

Today, cancer is one of the leading cause of mortality around the world and according to WHO, “Lung, liver, breast, stomach, and colorectal are the major cancer forms that lead to enhancing the mortality rate.”

Undoubtedly, with the advancements in the therapeutics, there are cancer interventions available today, which significantly can help in detecting and effective treatment of around one-third of the cases. However, the exact causes behind increasing cancer risk and rate must also be assessed before treating cancer and under these causes, environmental carcinogens are also counted.

Let’s find out how these hidden environmental carcinogens affect the human body and associated with the cancer progression:

The environment wherein we live can be categorized into three fundamental elements:

  1. Physical: Energy of one or another form
  2. Biological: All living entities
  3. Chemical: Natural or man-made components

People can come in contact with this element via three mediums viz. air, soil and water. All factors associated with these environmental elements, for instance, physiological stress, toxic chemicals, infectious agents and physical factors all play a significant role in the onset of many human diseases including various types of cancer.

Let’s explain in little detail:

  • Physical environmental factors & cancer
  • Chemical environmental factors & cancer
  • Occupational factors & cancer
  • Conclusion

Physical Environmental Factors & Cancer

Electromagnetic radiations from low frequency to relatively high frequency viz. radio, microwaves, infrared, ultraviolet, X-rays, visible and gamma rays, all can have some impact on human health. Specifically, high-frequency radiations like gamma rays and subatomic radiations like beta rays are known as ionizing radiations and exhibit a significant impact on the human body.

These ionizing radiations are known as established carcinogen that present role in both initiation and progression of cancer. It can be evident from the outcomes of studies done on early radiologists, atom bomb victims of Japan and radium dial painters.

Other than these ultraviolet rays also found to have a significant association with skin cancer. Ultraviolet irradiation can alter the healthy DNA configuration by generating the reactive oxygen species, which ultimately makes a friendly environment for carcinogenesis. Also, the mother’s exposure to obstetric X-rays can increase the risk of childhood cancers.

Chemical Environmental Factors & Cancer

Throughout history, one of the chemical carcinogens which gained the most attention is the tobacco smoke. This chemical carcinogen shows a potential association with oral, breast, lung, and bladder cancer development.

Today, you can find more types of chemical carcinogens, such as, industrial, manufacturing, agricultural including pesticides and insecticides, chemical contamination of water and air pollution (indoor and outdoor), which significantly associated with cancer.

Other than these, building paints, garden pesticides, chemicals used for home cleaning can also include in this category.

There have been three stages involved in chemical carcinogenesis i.e. initiation, promotion and progression. Each stage is featured by biochemical and morphological changes that result due to epigenetic/genetic alterations. These genetic changes involved: mutations in genes that control DNA repair, cell proliferation and cell death.

On the other hand, non-genotoxic mechanism of chemical carcinogenesis involved immunosuppression, inflammation, reactive nitrogen species, reactive oxygen species, receptor activation and epigenetic silencing.

These genotoxic and non-genotoxic impacts of these carcinogens leads to genetic instability, hyper-mutability, resistance to apoptosis and loss of proliferation control, which further related to cancer progression.

Occupational Factors & Cancer

Occupational cancer is lead partly or wholly via exposure to a carcinogen at the workplace. Positive associations have been seen for occupations like miners, metal moulders, cooks, brick masons, fisherman, firefighters, carpenters, plasterers and sailors. The leather footwear, rubber and the meat industries are the higher stakes of getting occupational cancer.

The major exposures in such job fields are mineral and metal dust, wood dust, N-nitroso compounds and coal dust. The workers working in mining and milling of metal, felt-hut manufacturing and thermometer production are exposed to mercury, which is one of the major occupational carcinogens to raise the incidences of lung cancer.

Even the farmers show an elevated risk of getting stomach cancer in the majority of studies conducted around the world. The exposures at farming place might are the inorganic and organic dust, diesel fuels and fertilizers. The farmers also found to at higher risk of getting Hodgkin’s lymphoma.

Ovarian cancer in women is also subjective to many occupational carcinogens, such as aromatic hydrocarbon solvents, man-made vitreous fibres, gasoline, asbestos and bather dust. Moreover, exposure to endosulfan found most contaminated food or water also associated with the increasing risk of getting breast cancer.

S.No.

CANCER

OCCUPATIONAL CARCINOGEN

1 Lung Asbestos, coke oven fumes, coal, nickel refining, chromium compounds, arsenic, cadmium
2 Bladder Rubber industry, benzidine, leather industry, aluminum components
3 Larynx Asbestos, mustard gas, isopropyl alcohol
4 Pharynx Mustard gas, formaldehyde
5 Nasal cavity and sinuses Formaldehyde, isopropyl alcohol, mustard gas, nickel refining, wood dust, leather industry
6 Skin Coal tars, UV rays, mineral oils, arsenic
7 Liver Vinyl chloride, arsenic
8 Soft-tissue sarcoma Chlorophenoxy herbicides, chlorophenols
9 Mesothelioma Asbestos

Conclusion

There are pieces of evidence which support the positive association between the environmental carcinogens and cancer progression.

This necessitates the strong primary prevention attempts to lower or eliminate the chemical, physical and occupational exposures, which are known to be potent carcinogens. This further emphasizes the call for a better understanding directed at managing exposure to such carcinogens.

Also, the health caregivers must carry out the awareness programs that can inform and educate the people about the carcinogenic effects of the environmental pollutants and teach regarding associated health and hygiene practices to reduce the risk of getting cancer.

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