Expression of SNORD42A in AML patient samples. (A) SnoRNA expression in 63 AML samples at the time of diagnosis in reads per million (RPM). SnoRNAs were ranked by median expression. SNORD42A ranked among the highest expressed snoRNA in this patient cohort. (B) Patient samples were split into high- and low-expressing SNORD42A groups using the median. Percentage of bone marrow blasts in each group is shown (mean ± standard deviation [SD], P = .012, Student t test). (C) Percentage of blasts in peripheral blood in SNORD42A high- and low-expressing AML patients. Data are shown as mean ± SD; P = .08, Student t test. (D) Correlation between percentage blasts in the bone marrow and expression of SNORD42A in the AML samples (Spearman correlation r = +0.28, P = .029). (E) Expression in reads per million of SNORD42A in patients with good and intermediate molecular risk. Data are shown as mean ± SD; P = .0112, Student t test. (F) SNORD42A expression in AML and healthy hematopoietic cell populations. In total, we measured 9 AML, 5 CD34⁺, 5 monocyte, and 5 granulocyte samples. Data were normalized to the mean of cord blood CD34⁺ cells using 5S rRNA as an internal control, and the median levels are indicated.