Scientists now understand how certain changes in DNA can cause normal lymphocytes to become lymphoma cells. DNA is the chemical in each of our cells that makes up our genes – the instructions for how our cells function. We usually look like our parents because they are the source of our DNA. But DNA affects more than just how we look.
Some genes contain instructions for controlling when our cells grow, divide into new cells, and die at the right time. Certain genes that help cells grow, divide, or live longer are called oncogenes. Others that slow down cell division or cause cells to die at the right time are called tumor suppressor genes. Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes.
The DNA in each human cell is packaged in 23 pairs of chromosomes. Changes in chromosomes are sometimes seen in skin lymphoma cells, but there is no single chromosome change that is common to all skin lymphomas. In some cases, part of one of the chromosomes is lost (known as a chromosomal deletion). Translocations, in which DNA from one chromosome breaks off and becomes attached to a different chromosome, are another type of change seen in some skin lymphomas. When these types of chromosome changes happen, oncogenes can be turned on or tumor suppressor genes can be turned off.
Scientists are learning about the exact genes involved in this process and how they may cause lymphoma and other cancers. This information is being used to develop new tests for detecting and classifying certain types of non-Hodgkin lymphoma, as well as for developing new treatments. Even though researchers have found some of the key DNA changes that cause lymphoma, they still do not know why these changes occur. The immune system seems to play an important role in some cases of lymphoma. People with immune deficiencies (due to inherited conditions, drug treatment, organ transplants, or HIV infection) have a much greater chance of developing lymphoma than people without an immune deficiency.
Statistics
- Skin lymphomas (T-cell or B-cell, mycosis fungoides, or Sezary syndrome) are very rare.
- In the statistics below, only 5% of those diagnosed with Non-Hodgkin lymphoma will have skin lymphoma. In BC, that might be about 45 people each year.
- B.C. statistics for these cancers are included with Non-Hodgkin Lymphomas.
- Canadian statistics are also grouped in with other Non-Hodgkin Lymphoma. Skin lymphomas are only a very small number of these cases.