Cancer in any form is a deadly disease. But when it affects the most
vital components of the body then their fatality increases manifold.
One such type of cancer is cancer of the blood, technically known as
leukemia. Blood is the most important tissue of the body. It is the
connective tissue which carries and supplies oxygen and other vital
elements to the remotest parts of the body. The importance of blood
can be understood by the fact that it is the most important of all the
connective tissues which provide the nutrients and other vital
elements to the body.

The most dangerous feature of leukemia is that it is related to the
blood which has access to almost all body organs including the all
important brain and heart. The incidence of cancerous cells being
carried to the different parts of the body increases drastically due
to this fact. Another striking aspect of the blood cancer is that it
affects the leukocytes or the "white blood corpuscles" of the blood.
These are the ones that protect the body from external infections.
Thus the immunity of the body is seen to decrease drastically due to
leukemia. The main effect of the disease is that the body starts
producing infected and abnormal cells that hinder the function of
blood i.e. carrying of oxygen.

A patient suffering from leukemia is seen to loose weight due to
anemia. This happens because the cancerous cells are unable to carry
the hemoglobin properly

http://www.dontplayplay.com/html/horoscope/20060925/8189.html