CD34 and acute lymphoblastic leukemia: Univariate analyses indicated that CNSL relapse might be associated with the following factors: ALL as the underlying disease (hazard ratio [HR] = 8.978, 95% CI = 1.204–66.920, p = 0.032), partial remission/no remission (PR/NR) status before transplantation (HR = 3.841, 95% CI = 1.259–11.720, p = 0.018), infused CD34+ cell count (HR = 0.180, 95% CI = 0.039–0.820, p = 0.072), and a history of CNSL before UCBT (HR = 4.825, 95% CI = 1.505–15.470, p = 0.001).