Cancer is the term given to a group of over 100 diseases, which originate with the growth of abnormal cells inside the body. Instead of dying like a normal cell would in its life cycle, cancerous cells continue to grow and divide into new abnormal cells, eventually growing out of control.

Lymphoma is a cancer that originates in the lymph system (also called the lymphatic system), which is a part of our immunity. Its characteristics include the formation of solid tumours in the immune system. This cancer affects the immune system cells called lymphocytes, (they are white blood cells).

Lymphatic cancers are classified by the type of immune cells affected, and there are two major types - Hodgkin's and non-Hodgkin's lymphoma. Almost 90% of lymphomas are non-Hodgkin's lymphomas while the remaining 10% are Hodgkin's lymphomas.

In non-Hodgkin's lymphoma, it is the B-cells and T-cells that are affected, both of them being types of white blood cells that play special roles in a person's immunity. In Hodgkin's lymphoma, the cancer cells are generally an abnormal growth of the type B lymphocyte, which is named the Reed-Sternberg cells. There are various subtypes of Hodgkin's lymphoma, which are classified according to their differences as seen under the microscope.

What causes lymphoma?

For most cancers, most researchers are still trying to figure out how they are caused. It is true for lymphoma as well - doctors do not know what causes it but it is more likely to occur in certain people as compared to others.

The risk factors that make lymphoma more likely to occur in a person have been identified below -

Non-Hodgkin's Disease

Maximum number of cases of non-Hodgkin lymphomas are in people of 60 years of age and over
There are different kinds of non-Hodgkin's lymphoma which are spread across the sexes
This disease is more common in developed nations of the world like the US
Certain chemicals which are used in agriculture have been linked to this disease, just like nuclear radiation exposure
Immune deficiency (caused by HIV) or in organ-transplantation can lead to non-Hodgkin lymphomas
People with autoimmune diseases (where the immune system attacks the body's own cells) are at greater risk for developing this disease.
There are some bacterial infections which increase the risk factor

Hodgkin's Disease

Those who have been infected with Epstein-Barr virus are at greater risk
There are two specific groups which are most affected - people who are in their 20s, and people over the age of 55
It is a little less common in women than in men
It is very uncommon in Asia
Genetics - If a sibling or parent has the condition, the risk is slightly higher for a person. The risk doubles if there is an identical twin with the same disease.
It has been observed that people from higher socioeconomic status are at greater risk HIV infection