The k-TSP method was able to identify 18 genes which are able to discriminate Acute Myeloid Leukemia (AML) from Acute Lymphoblastic Leukemia (ALL), and 9 of them (CD33, ZYX, TCF3, CST3, ATP2A3, CCND3, TOP2B, CTSD and DF) were already pointed out by Golum and colleagues to be associated with AML and ALL. The gene discussed is CTSD; the disease is acute lymphoblastic leukemia.