TUG1 and acute lymphoblastic leukemia: According to the quantiles of lncRNA TUG1 expression in Ph− ALL patients, patients were divided into four tiers: tier 1 (ranked in 0%~25% among all patients), tier 2 (ranked in 25%~50% among all patients), tier 3 (ranked in 50%~75% among all patients), and tier 4 (ranked in 75%~100% among all patients).