Increased levels of cyclin D1 negatively impacts on acute lymphoblastic leukemia overall survival

ABSTRACT

Background: Cyclin D1 is a protein essential for transition from G1 to S phase during cell cycle progression, which has an oncogenic potential and is highly expressed in several human malignancies. However, in view of the heterogeneity of the findings in the literature, the prognostic value of cyclin D1 expression still needs to be validated in different cohorts of adult acute lymphoblastic leukemia (ALL) patients. Methods: Bone marrow samples from 13 healthy donors and 45 adult patients with acute lymphoblastic leukemia were included. Cyclin D1 gene expression was evaluated by quantitative PCR. For statistical analysis, Mann­Whitney test, Fisher's exact test, Chi-squared test and Cox regression were used, as appropriate. All p values were two-sided with a significance level of 5%. Results: Cyclin D1 mRNA levels were similar between primary cells from ALL patients and healthy donors. In ALL patients, high cyclin D1 expression was associated with older age at the diagnosis, presence of BCR-ABL1, and lower white blood cell counts. Importantly, increased cyclin D1 expression was an independent factor that predicted worse overall survival in our adult ALL cohort. Conclusion: Increased levels of cyclin D1 negatively impacted on ALL survival outcome, suggesting that this gene is involved in the malignant phenotype of ALL.