What do leukemia sufferers have too many of?

Question

Even though I know the answer, I searched Google under the key words "leukemia" to get these possible sources:

http://en.wikipedia.org/wiki/Leukemia
http://www.cancercenter.com/leukemia.cfm?source=google&c=1230:1
http://www.cancer.gov/cancertopics/types/leukemia
http://www.medicinenet.com/leukemia/article.htm

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.

I hope this helps. Thanks for asking.