Expression of Oct3/4 isoforms and its association with the risk of relapse in acute lymphoblastic leukemia

Oct3/4 is a transcription factor that maintains the stemness of both embryonic and adult stem cells. The Oct3/4 gene produces three isoforms: namely, Oct3/4A, Oct3/4B and Oct3/4B1. Increased Oct3/4 expression is associated with lower survival rates and chemoresistance in patients with cancer. The present study examined the association between Oct3/4 isoforms expression and the risk of relapse to acute lymphoblastic leukemia (ALL). The mRNA expression levels of Oct3/4A, Oct3/4B and Oct3/4B1 were analyzed using reverse transcription-quantitative PCR in 51 patients with ALL and 12 children without ALL. The results of the present study indicated that the mRNA expression levels of Oct3/4A (P=0.008), Oct3/4B (P=0.019) and Oct3/4B1 (P=0.025) were significantly elevated in patients with ALL. Moreover, elevated mRNA expression levels of Oct3/4A [odds ratio (OR)=13.33; 95% confidence interval (CI): 1.57-112.99; P=0.018), Oct3/4B (OR=20.00; 95% CI: 2.37-168.64; P=0.006) and Oct3/4B1 (OR=7.26, 95% CI: 1.43-36.93; P=0.017) isoforms were associated with a heightened risk of relapse in patients with ALL. The multivariate analysis, stratified using established prognostic factors, identified Oct3/4A, Oct3/4B and Oct3/4B1 mRNA expression levels as independent prognostic markers of ALL. The results of the present study also indicated that the expression levels of Oct3/4A (P=0.0112), Oct3/4B (P=0.0044) and Oct3/4B1 (P=0.0071) were significantly elevated in CD34⁺/CD38^- patients with ALL compared with those in CD34⁺/CD38⁺ patients with ALL. Thus, increased mRNA expression levels of Oct3/4A, Oct3/4B and Oct3/4B1 may be associated with a poor prognosis in patients with ALL.