Solute carriers as potential oncodrivers or suppressors: their key functions in malignant tumor formation.

Solute carrier (SLC) transporters are primarily known for their function in the transportation of various exogenous/endogenous substances via influx/efflux mechanisms. In addition to their diverse role in several tumor-modulating functions, such as proliferation, migration, angiogenesis, epithelial-mesenchymal transition (EMT), epigenetic modification, chemoresistance, immunoregulation, and oncometabolism, influx/efflux-independent contributions of SLCs in the activation of various signaling network cascades that might drive metastatic tumor formation have also been uncovered. Disappointingly, even after two decades and the discovery of >450 SLCs, many of their members remain orphans in terms of cancer pathogenesis. In this review, we summarize the current understanding of the tumor-modulating functions, mechanisms, and complexity of SLCs, as well as their potential as targets for cancer therapy.