Impact of BCL-2 Expression on Course of Disease in Neuroblastoma.

Objective:  The antiapoptotic BCL-2 protein has implications for maturation and differentiation of neural tissue and acts as a strong modulator of carcinogenesis in different tumors. Recent research focuses not only on its benefit as a prognostic factor, but also as a potential therapeutic target. The role of BCL-2 in neuroblastoma, the most common extracranial solid tumor in childhood, remains controversial. The aim of our study was to determine the gene expression level of BCL-2 in a large cohort of neuroblastoma patients and its correlation with clinical parameters.

Methods:  Tumor samples and clinical data were collected from 100 neuroblastoma patients treated according to the NB2004 protocol of the German Society of Pediatric Oncology and Hematology. BCL-2 gene expression levels were measured by quantitative reverse transcription polymerase chain reaction and correlated with clinical parameters.

Results:  BCL-2 expression was detected in all tumor samples. Relative BCL-2 expression levels were higher in females versus males (1.839 vs. 1.342; p = 0.0143), in patients with low versus high International Neuroblastoma Staging System stage (2.051 vs. 1.463; p = 0.0206), in nonmetastatic versus metastatic disease (1.801 vs. 1.342; p = 0.0242), as well as in patients without presurgical chemotherapy (2.145 vs. 1.402; p = 0.0016), but was not associated with overall survival and MYCN amplification.

Conclusion:  Our study demonstrates the ubiquitous expression of BCL-2 in neuroblastoma and suggests the possibility for targeted therapy with BCL-2 inhibitors, even in lower-stage neuroblastoma. It also underlines the need for further research on concomitant genetic alterations for a better understanding of the impact of BCL-2 on this pediatric tumor type.