Carcinogenic, Mutagen and Teratogenic Substances

writer Zeynep Aktas

Great care must be taken when working with substances that cause irreversible and cumulative destruction in small doses. These can cause the formation of malignant tumors (carcinogen), alteration of genes (mutagen), or abnormal births (teratogen). So what are these substances?

1. Carcinogenic Substances

A carcinogenic substance, that is, a substance that promotes cancer formation, is a radionuclide or radiation. This may be due to its ability to damage the genome or to disruption of cellular metabolic processes. Although the public generally associates carcinogenicity with synthetic chemicals, Both natural and synthetic substances can be carcinogenic.

There are many natural carcinogens. Produced by the fungus Aspergillus flavus, which grows on stored grains, nuts, and peanut butter, aflatoxin B1 is an example of a potent, naturally occurring microbial carcinogen. Some viruses, such as hepatitis B and human papillomavirus, have been found to cause cancer in humans. The first virus shown to cause cancer in animals was the Rous sarcoma virus, discovered by Peyton Rous in 1910. Among other infectious organisms that cause cancer in humans are some bacteria.

Substances that cause cancer are basically divided into 3 classes:

Group A1: Substances known to cause malignant tumors in humans.
Group A2: Substances that cause cancer in experimental animals and are thought to pose a similar danger to humans.
Group B: Substances that are at risk of causing cancer.

The International Agency for Research on Cancer (IARC), on the other hand, divides carcinogens into 4 classes based on strong evidence of the dangers of carcinogens to humans:

1: Carcinogenic to humans,
2A: Possible carcinogen to humans,
2B: Possible carcinogen to humans,
3: It cannot be classified according to its carcinogenicity to humans,
4: Probably not carcinogenic to humans.

In addition, in accordance with the laws, regulations and international agreements put forward by various nations, there is an obligation to indicate the hazards of chemical substances with the risk statements (R codes) on the labels. According to this R45 or R49 chemical substances bearing the codes "carcinogen" in the scope of; R48 If the items bearing the code “a substance with a high risk of causing cancer in the long term” accepted under.

Some cancer-causing substances are given in Table 1.

carcinogenic substances

Table 1. Some carcinogenic substances, their areas of effect and their sources

In addition to the items in Table 1:

I. Gasoline (contains aromatics)
ii. Lead and its compounds
iii. Alkylating antineoplastic agents (eg mechlorethamine)
iv. styrene
v. Other alkylating agents (eg dimethyl sulfate)
vi. Ultraviolet radiation from the sun and UV lamps
vii. Alcohol
viii. Substances such as other ionizing radiation (X-rays, gamma rays, etc.) can cause cancer.

2. Mutagen Substances

Mutagen is the name given to a substance or an agent that causes mutations. A mutation is a change in the DNA sequence of an organism. Therefore, any agent that causes a DNA sequence change is termed a mutagen.
A mutagen can cause different types of mutations due to addition, deletion or translocation of sequence bases. Therefore, all mutagens are capable of mutagenicity.

By the European Union, mutagenic substances are handled in 3 groups:

Category 1(T): Substances known to be mutagenic to humans
Category 2(T): Substances that can be considered mutagenic to humans.
Category 3(Xn): Substances with potential for mutagenic effects in humans, but for which data are insufficient. Some mutagenic substances are given in Table 2.

mutagenic substances

Table 2. Some mutagenic substances

3. Teratogenic Substances

Teratogens are substances that cause direct and specific effects on sexual function and fertility. These; alterations in the reproductive system, adverse effects on the onset of puberty, production and transport of germs, abnormal reproductive cycle, changes in sexual behavior, fertility, childbirth, pregnancy outcomes, or other functions related to the integrity of the reproductive system. These include effects transmitted to breastfed infants.

The effects of teratogenic substances on the health of pregnant women may vary depending on the time of exposure. For example, exposure during the first trimester of pregnancy can result in induction of metabolic disorders in the maternal body, abnormal embryogenesis, congenital disability or miscarriage. Exposure in the last six months can slow the growth of the fetus, affect brain development, or cause premature birth.

At the same time, fetal development may be impaired through hereditary changes (epigenetic mechanisms) in egg or sperm cells; this does not cause a fundamental change in the organism's DNA sequence, but instead, non-genetic factors cause the organism's genes to behave differently.

Some teratogenic substances are given in Table 3.

teratogenic chemicals and drugs

Table 3. Some teratogenic chemicals and drugs


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About the Author

Zeynep Aktas

Born in 1998, a Chemical Engineer who believes that science will save the world and works to become a scientist.

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