Adult B-Cell Acute Lymphoblastic Leukaemia Antigens and Enriched Pathways Identify New Targets for Therapy

Background: Adult B-cell acute lymphoblastic leukaemia (aB-ALL) is characterised by abnormal differentiation and proliferation of lymphoid progenitors. Despite a significant improvement in relapse-free and overall survival for children with B-ALL, aB-ALL has a particularly poor prognosis with a 5-year survival rate of 20%. First remission is achieved for most patients but relapse is common with a high associated mortality. New treatments such as immunotherapy offer an opportunity to extend remission and prevent relapse.  Methods: aB-ALL antigens were identified using different sources - immunoscreening, protoarrays, two microarrays and one cancer-testis antigen (CTA) database, and a review of the genomic analyses of aB-ALL. 385 aB-ALL-associated gene products were examined for their association with patient survival. Results: We identified 87 transcripts with differential expression between aB-ALL and healthy donors, and 42 that were associated with survival. Enrichr analysis showed that the Transforming Growth Factor-β (TGFβ), Wnt and hippo pathways were highly represented (p<0.02). We found that SOX4 was upregulated in all types of B-ALL, while ROCK1 was upregulated in all types of B-ALL (p<0.001 except t(8;14)) and along with SMAD3 and TEAD4 were associated with survival (p=0.0008, 0.05 and 0.001 respectively).  Expression of each aB-ALL antigen was verified by qPCR but only TEAD4 showed significant transcript upregulation in aB-ALL compared to healthy donor CD19+ cells (p=0.01).  Conclusions: We have identified a number of antigens and their pathways that play key roles in aB-ALL and may act as useful targets for future immunotherapy strategies.