Non-Hodgkin's lymphoma is a group of cancer types that develop from white blood cells, also called lymphocytes. Non-Hodgkin's lymphomas can be slow-growing, or fast-growing and aggressive, and they can affect either the B-cells or T-cells of the blood. The full range of causes of non-Hodgkin's lymphoma are not yet well understand, but scientists have uncovered a number of factors that may cause non-Hodgkin's lymphoma.
Chromosome Translocations
Chromosomes are large pieces of DNA that contain a number of genes. Most of the cells in the body contain two sets of 23 chromosomes, which contain thousands of genes that are arranged along the chromosomes. Chromosome translocations occur when the chromosomes become mutated, so the arrangement of genes on the chromosomes changes. These types of mutations can result because of exposure to radiation.
Chromosomal translocations play a role in the development of non-Hodgkin's lymphoma. In a 1994 study published in Cancer Genetics and Cytogenetics, Dr. H. Ohno found that non-Hodgkin's lymphoma patients had chromosome translocations corresponding to specific regions of the chromosomes. Specifically, Dr. Ohno found that translocations in chromosome 3 has links to cancer. Deletion of key genes on chromosome three therefore likely helps to cause non-Hodgkin's lymphoma.
AIDS
The risk of developing non-Hodgkin's lymphoma increases for patients who have AIDS, an infection of lymphocytes by the human immunodeficiency virus, HIV. HIV infects white blood cells by entering the cell, generating viral DNA and inserting that viral DNA into the chromosomes of the white blood cell. Inserting viral DNA into chromosomes may disrupt the function of genes-if the viral DNA is inserted in the middle of a gene, that gene may become non-functional. If viral DNA disrupts genes involved in protecting the cell from cancer, then the cell may become cancerous, leading to diseases like non-Hodgkin's lymphoma.
Patients with AIDS have a much higher risk of developing non-Hodgkin's lymphoma. Canwest Publishing reports that one in ten patients with AIDS eventually develop non-Hodgkin's lymphoma, which is 60 times the rate of non-Hodgkin's lymphoma without AIDS. Further research into the link between AIDS and non-Hodgkin's lymphoma will shed light onto the definitive cause of this cancer in AIDS patients.
Chemotherapy
Chemotherapy, the use of toxic drugs to treat many forms of cancer, can cause non-Hodgkin's lymphoma. Patients who have received chemotherapy for another form of cancer have up to a 30-fold increase in their chance of developing non-Hodgkin's lymphoma in the future, according to Antigenics.
The reason for this may be that some chemotherapy drugs work by targeting rapidly-dividing cells in the body, and causing DNA damage. This leads to cancer cell death, but also affects normal cells, such as blood stem cells within the bone marrow. If chemotherapy leads to an increase in genetic mutations in blood stem cell cells, this could lead to non-Hodgkin's lymphoma. Further research into the specific effects of chemotherapy on non-Hodgkin's lymphoma will more thoroughly explain by cancer patients have an increased risk of developing lymphoma in the future,
