Leukemia is a malignant condition of blood in which there is proliferative, purposeless increase of white blood cells in the blood, along with premature cells. The condition usually ends fatally. The total leukocyte count in a normal man ranges from 50000-9000. A mere increase in leukocyte count is up to 11,000 / cc is known as leukocytosis where as abnormal increase is above 25,000 / cc is leukocyte or blood cancer. A decrease in WBC count is called leukopenia.