Cancer in general

Cancer is not a single disease rather it is a general term used to describe various malignant tumours that affect all forms of higher organisms including animals and plants. More than a hundred types and sub types of cancer are known to affect the human beings.

Cancer can be defined as an abnormal growth of cells in any tissue or organ of body. Cancer cells have potential to spread and grow in other parts of the body. It preys on the host and continues to grow indefinitely competing with normal cells of the body for nutrition.

Over a period of time and with continued exposure to carcinogens, cancer cells accumulate further mutations and acquire more malignant characters such as, ability to move and invade the surrounding tissues, ability to create new blood vessels for nourishment of cancerous growth, ability to travel and grow in distant parts of the body and acquire ability of limitless replication that makes cancer cells immortal.

Chemotherapeutic drugs may induce further mutations in cancer cells making them resistant or refractory to the chemotherapy.

Normal cell division is a highly regulated mechanism, which is controlled by genes (made of DNA). Cancer causing agents(known as carcinogens) include mutations in the growth regulatory genes by damaging DNA that leads to loss of control over the normal cell division. It proliferates indiscriminately usually by forming a mass known as malignant tumour or simply 'cancer'.

The incidence of cancer is rising alarmingly and we are constantly exposed to a variety of carcinogens in the food we eat, the water we drink and the air we breathe. Our single meal may contain a dozen of carcinogens in the form of residues of pesticides and insecticides.

Radiation emitted by X-rays, CT scans, cell phone towers, computers and other electrical appliances have carcinogenic effect.

Likewise there is a long list of chemical, physical and geographical carcinogens that can cause cancer.

Transformation of a normal cell into a cancerous cell is probably not such a critical event in the genesis of cancer rather it is the inability of immune cells of the body to identify and destroy the newly formed cancer cells when they are few in numbers. It is observed that the risk of cancer is multiplied in those persons, whose immune system is suppressed due to other forms of serious illness they have undergone.

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