It can be genetic, lifestyle choices, or just happen at random like most cancers.
Leukemia.
Nope. But it can help diagnosing if you got cancer by confirming it's something else. To detect cancer you need to do Biopsy
No. There is a rare form of leukemia which is caused by systemic mastocytosis but most of us with the disease will not get it.
there is no ICD code per se for ' blood cancer', but there are codes for blood disorder, leukemia etc