When AML patients were classified into two groups using the median of ICOSL positivity, cases in high ICOSL group (n = 61, named ICOSLhigh AML) showed a short but not statistically significant overall survival and a markedly shorter disease-free survival compared with ICOSLlow AML cases (n = 60; Figure 6A). This evidence concerns the gene ICOSLG and acute myeloid leukemia.