Try to imagine a single type of cell giving rise to nearly thirty different types of cancer - all with one name. Lymphoma - simply in the nodes, a mass in your brain, a disease of your stomach, or lesions all over your skin. It's not simply a matter of location. The behavior changes with the type and so does the treatment and the outcome.
Even a couple of decades back, what the pathologist saw under the microscope with simple stains was all that we had to identify the type of lymphoma. And there were only a few types of lymphoma that could be distinguished. However, it often turned out that the behavior of the same type of tumor was different in different individuals. Clearly, we were missing something.
As medicine moved from cells to molecules, techniques were devised to identify some specific molecules that were found on the surface of cells. When these were applied to lymphoma cells, things took a dramatic turn. It turned out that lymphomas were not simply a handful of different types, but a lot more complicated.
On the surface of lymphocytes, the cells that are transformed to lymphomas, lie some unique molecules. These were named 'cluster differentiation' or CD markers. There are around eighty such markers identified until now. As normal lymphocytes develop from new cells to mature cells, these markers change. It was found that lymphomas that previously looked similar under the microscope had different markers on their surface. When that happened, they acted like different diseases altogether.
Today, the diagnosis of lymphoma simply isn't complete unless a couple of lymphoma markers are first identified. To put a particular lymphoma in the proper group, doctors often have to put your biopsy tissue to a series of marker tests called 'immunohistochemistry'.
It doesn't stop there. Some special markers (one of them called bcl-2) can even tell the doctor how well your disease will fare. Some others (like CD20) are a pointer to whether a particular treatment will work. As more and more research goes into these markers, new uses are coming up all the time. Truly, lymphoma has entered an era of molecules.
