What is Cancer – Basics, Causes, Formation of a Cancer Cell, Onset of the Disease
Cancer is a class of diseases which can affect people of all ages. In 90-95 percent cases, lifestyle and environmental factors cause the disease. Some of these factors are diet and obesity (30-35%), tobacco (25-30%), infections (15-20%), stress, environmental pollutants, radon exposure, radiation, stress, and lack of physical activity. In the remaining 5-10% cases, it is genetics which causes this disease.
There are more than 100 known types of this ailment. They can be broadly placed under two categories, namely the benign type or the malignant type. In either of the cases, healthy cells of the body turn into rogue ones. In the former type, these harmful cells restrict themselves to a particular site in the body.
In the later type, the harmful cells grow uncontrollably, affect the nearby healthy cells and spread to fresh locations of the body too. Research is under-way in trying to clearly explain the mechanism behind the lifestyle and environmental factors causing cancer. This article tries to understand how cancer is caused by genes.
The Basics to Understand Cancer:
All living organisms on this planet are made of cells. These are the basic units of life. Group of cells form a tissue. A collection of tissues forms an organ of the body. Functioning of these organs can be broken down to the cellular levels.
At the centre of a cell, is its nucleus. It contains certain chemical molecules called the DNA. A structure made up of these molecules is called the chromosome. Group of chromosomes form a gene. It is the instruction followed by any cell in order to perform its function. The genes are read by another important class of chemical molecules called the RNA. After reading the instructions (genes), the RNA molecules produce chemicals called proteins. The proteins ultimately carry out the functions of the cells.
What are the Causes of Cancer?
The functions of the cells are governed by certain basic properties. Cell replication and apoptosis are two such fundamental properties. Old cells are replaced by new cells by a process called cell division. During this process, the set of instructions from the parent cells are passed on as it is to the daughter cells in ideal cases. In this way, cell replication takes place. The old or the parent cells die after this event. It is a programmed death called apoptosis technically.
But in actual circumstances, cell replication does not take place as it should ideally. As a result, a daughter cell receives a new but erroneous genetic structure or instruction to follow. This event is called mutation. Changes in the genes caused by mutation are unavoidable and happen inevitably.
How a Cancer Cell is Formed?
Initially, the number of the daughter cells with erroneous genetic instructions in them are low in number. But as they undergo cell division and become parent cells themselves, they pass on these erroneous instructions to their daughter cells. These instructions can be:
- Not to behave like normal cells and grow in an uncontrollable manner.
- Not undergo apoptosis and interfere with the normal functioning of other cells.
- There is an inherent error-correcting system in every cell. Mutation can cause malfunction in this vital system leading to self-amplification of errors per cell division.
- Cells function together as a unit through a signalling system of communication. Mutation can disrupt this system causing wrong signals being transferred between cells.
The less number of errors in the initial stages multiply exponentially as the new bunch of malignant cells grow uncontrollably without any death. This cascade of events gradually leads to change in the entire structure of instructions, giving birth to a cell which has behaviors and functions in complete contrast to normal healthy cells. It is the cancer cell.
How the Disease Takes its Known Form?
True to its nature, a cancer cell releases some toxic proteins which convert a group of healthy cells of an organ into malignant ones. The formation is called a tumor. If it restricts its actions to the site of origin, it is called the benign type.
But, the cells of the other tumor type, the malignant ones, as per their property of uncontrollable growth and no death, can invade the healthy cells in the fresh locations of the body too. This process is called the metastasis which spreads the ailment to the entire body and makes it incurable.