Hodgkin's Disease

Cancer is a general term that refers to a condition in which a particular type of cell within the body begins to multiply in an out-of-control fashion. This may mean that cancer cells multiply more quickly, or it may mean that cancer cells take on abnormal characteristics. For example, at a very early stage in embryonic development (development of a fetus within the uterus), generic body cells begin to differentiate. Cells acquire specific characteristics which ultimately allow liver cells to function as liver cells, blood cells as blood cells, brain cells as brain cells, and so on. Thus, cancer can be considered to be a process of "de-differentiation." In other words, a specialized type of cell loses whatever controls govern the expression of its individual characteristics and instead revert to a more embryonic cell. Such cells also lose their sense of organization and no longer position themselves appropriately within their resident tissue.

Cancer cells can also acquire the ability to invade other tissues. Normally, for example, breast cells are found only in breast tissue. However, cancerous breast cells can invade into other tissue spaces, so that breast cancer can spread to bone, liver, brain, etc.

Lymphoma is a cancer of the lymph system. Depending on the specific type, a lymphoma can have any or all of the characteristics of cancer. These characteristics include rapid multiplication of cells, abnormal cell types, loss of normal arrangement of cells with respect to each other, and invasive ability.