ADVERTISEMENT

A Closer Look At Cancer

Why do we get cancer?Ā 

This question has bothered patients and doctors for centuries. But, perhaps the question should rather be: why do we not get cancer?

ADVERTISEMENT

We get potential cancer many millions of times every day. Cancer is caused by missegregation, a common mistake in cell division where one daughter cell gets a chromosome too many, and the other a chromosome too few. This happens in 0.01 to 4 percent of cell divisions. It is a dangerous situation in dividing cells because, after that, cell division cannot be done correctly, as at least one new daughter cell will have a faulty chromosome number. If a cell with a surplus chromosome is allowed to divide, a daughter cell would end up with two surplus chromosomes, and the cellā€™s descendants would be on the way to acquire the many extra chromosomes typical of cancer cells.

The organism has a number of repair mechanisms to prevent missegrated cells from turning into cancer cells. The first is a roll-back of the division itself. If the dividing cell senses that a chromosome is not ending up in the right place, no cell wall is formed, and instead, the cell ends up with two nuclei or a nucleus with double the normal set of chromosomes. A second repair mechanism is ordering the cell never to divide again, called cell division arrest. Another important repair is ordering the cell to commit suicide, apoptosis. Finally, cells with the wrong chromosomes get eliminated by the immune system.Ā 

If a potential cancer cell slips past all these safeguards and also acquires the ability to metastasize, it can develop into a dangerous cancer. Metastases forming ability may be caused by mutation, but it may also be the result of a fusion of potential cancer cell and a white blood cell. The resultant cell moves as a white blood cell, but it does not die as a white blood cell, and instead, it divides as a cancer cell.

Carcinogenic agents typically work by disabling repair mechanisms. X-rays or radioactive substances induce mutations that inactivate a repair mechanism. People with inborn tendency to form cancers often have faulty repair mechanism genes.

ADVERTISEMENT

Cancer increases with age. One reason is that missegregation increases with age. Another important reason is that cells can only divide about 50 times after egg cell and sperm fused. After about 50 divisions, the shoe-lace like ends of the chromosomes have been cut off and the chromosomes unravel and stick together and break up in wrong places, creating numerous mutations. Such ā€œoldā€ cells do not usually divide, but if they do divide, they become mutation generators. Old people are close to the 50 division limit, where potential cancer cells become mutation factories.

Large, long-lived animals like elephants rarely get cancer, while small short-lived animals like mice often get cancer. Elephants have extra genes for repair mechanisms. Mice reach the cell division limit already after 10-15 divisions. Elephants keep potential cancers in check for a long time, whereas mice often develop cancer before they are one year old.

These findings are described in the article entitled Cancer follows chromosome missegregation when all endogenous repair mechanisms fail, recently published in the journal Medical Hypotheses. This work was conducted by Kjeld C. Engvild from the Technical University of Denmark.

Comments

READ THIS NEXT

Using Drones To Assess Subsurface Damage In Aircraft Materials

This research investigates the potential of using drones to inspect subsurface damage in composite aircraft materials. We develop a proof-of-concept […]

Rhomboidal And Triangular Four- And Five-body Problems: Planar Central Configurations

Researchers established that many stars are part of multiple–star systems. Moreover, the ratio of multiple-star systems in our galaxy is […]

Are Ruby-Throated Hummingbirds Flying Across The Gulf Of Mexico?

Many people find it hard to believe that the small, backyard birds encountered during particular seasons travel thousands of kilometers […]

Your Uncovered Lightbulbs Exposes Your Food To Chemical Hazards

Uncovered lightbulbs expose your food to the hazard of a broken lightbulb and to potential chemical contamination. Food hazards are […]

Multiple Strategies To Meet The Energy Costs Of Human Lactation ā€“ But Not Increased Energy Efficiency

For all animals, reproduction entails an investment of time and energy. Among humans, lactation (i.e., breastfeeding) is, perhaps surprisingly, the […]

Levosimendan: A FDA-Approved Drug Treating Heart Failure Also Blocks HIV-1 Reactivation

Human immunodeficiency virus type 1 (HIV-1) infection causes acquired immune deficiency syndrome (AIDS), which remains aĀ major public health concern. Combination […]

Mineral Dust Transport Both Drives Earth Systems And Responds To Changing Environmental Conditions

The transport of mineral dust (e.g. soil) through the atmosphere over thousands of kilometers represents an important component of Earth […]

Science Trends is a popular source of science news and education around the world. We cover everything from solar power cell technology to climate change to cancer research. We help hundreds of thousands of people every month learn about the world we live in and the latest scientific breakthroughs. Want to know more?