Relevance of AKT and RAS Signaling Pathways for Antibody–Drug Conjugate Immunotherapies in Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia is the most common cause of cancer-related death in children and represents a poor prognosis for patients in high-risk groups. Current treatment protocols are based on intensive polychemotherapy, which is associated with a significant toxicity profile. Due to their higher specificity and lower toxicity, immunotherapies based on monoclonal antibodies, in particular antibody–drug conjugates (ADCs), are revolutionizing cancer therapy. However, reports on the potential efficacy of ADC-targeted therapy in ALL and its subgroups are limited. Gene expression data suggest that potentially new ADC antigens are highly abundant in ALL subgroups and represent promising targets for cancer therapy. In addition, the PI3K/AKT and RAS/MAPK signaling pathways are often persistently activated in ALL and recent data showed that active feedback loops following inhibition of these pathways can lead to redundancy of cell surface receptors that can potentially serve as antigens for ADC treatment. Therefore, we provide here an overview of the most interesting receptors of the various ALL subgroups and discuss the influence that feedback loops of the PI3K/AKT and RAS/MAPK signaling pathways may have on increasing protein expression of the aforementioned receptors, which could lead to targeted combination therapy approaches in the future.