What causes cancer cells?
Cancer is the growth of abnormal cells in body. This growth is uncontrollable. It can start in any body part, organs and tissue. There is no specification of cells for cancer.
Genetics of cancer
Our body is composed of cells. Cells have many organelles including nucleus. Nucleus is a membranous bound organelle in both plants and animals. It is present in the center of cell in animals while in plants it is present at one side due to presence of large vacuole. Nucleus has hereditary material that is DNA. It has genetic information encoded in the form of genes. Genes control body function by forming proteins. There are many types of proteins and the important ones are enzymes.
Enzymes are biological catalysts. They control the rates of all biochemical reactions in the body like Krebs cycle, digestion, respiration and gluconeogenesis. Enzymes control all processes like urge for thirst, hunger and muscular activities. In short, body depends upon enzymes for controlling the rates of biochemical reactions.
Some receptors are also protein in nature. Genes have information for synthesize of receptors. They play important roles in transportation of many substances inside and outside of the cell. If there is wrong synthesize of receptor, wrong substance will enter in the cell and will lead to abnormality. Our immune system try to remove abnormal cells from body by engulfing or endocytosis. Sometime immune system succeeded in removing abnormal cells and sometime it may damage and defeated.
Cell division controlling proteins
Cells contain some proteins that control the rate of cell division. DNA synthesize these proteins. If the information in DNA has damaged then it will lead to the production of wrong proteins. Due to these abnormal proteins, cell will able to control the rate of cell division. Cell will become abnormal and multiply without any control. It will lead to cancer.
All above discussion tells us about the importance of DNA. If there is any mutation in DNA, there will be wrong synthesize of RNA and proteins. These two factors will lead to the formation of abnormal cells and their uncontrollable division. It will result in the form of cancer.
How mutations occur?
There are many causes of mutations in DNA. Some important risk factors are:
- Radiations (UV ray)
- Inherited history of gene mutation
- Errors during replication
- Chemicals such as tobacco
- Microorganisms like viruses and bacteria
- Inability of cell to repair DNA damage
These risk factors effect DNA in different ways and cause different mutations. DNA has genetic information in the form of sequence of nucleotides. Nucleotides contain phosphate group, ribose sugar and nitrogenous bases. DNA has double stranded structure and opposing nitrogenous bases form hydrogen bonds with each other. UV rays breaks the bonds between opposing bases and form bonds between adjacent bases.
Consequences of mutations
Mutation can cause a cell to produce abnormal proteins. These proteins will lead to abnormal cell division and improper functioning of cell. Due to this cell become abnormal and start to proliferate. It is the beginning of cancer. Once a cell is abnormal, it will continue to multiply and become immortal in nature.
How cancerous cells are different from normal cells?
Normal cell divides according to their need. Cells undergo apoptosis and necrosis when they have damaged. DNA control their rate of division. Normal cells are mortal in nature. Abnormal cells are immortal in nature. They multiply without any control. They do not undergo necrosis and apoptosis.
Cancerous cells can spread to other organs as malignant tumor.
At the beginning, cancerous cells remain confined to the place where they originate. This is the primary stage of cancer. It is less dangerous and curable. With the passage of time, cells spread to other organs and damage them in the form of metastatic tumor. This is the final stage and more dangerous than malignant tumor.