Plasma membrane Ca 2+ -permeable channels and sodium/calcium exchangers in tumorigenesis and tumor development of the upper gastrointestinal tract

The upper gastrointestinal (GI) tumors are multifactorial diseases associated with a combination of oncogenes and environmental factors. Currently, surgery, chemotherapy, radiotherapy and immunotherapy are relatively effective treatment options for the patients with these tumors. However, the asymptomatic phenotype of these tumors during the early stages poses as a significant limiting factor to diagnosis and often renders treatments ineffective. Therefore, new early diagnosis and effective therapy for upper GI tumors are urgently needed. Ca is a pivotal intracellular second messenger and plays a crucial role in living cells by regulating several processes from cell division to death. The aberrant Ca homeostasis is related to many human pathological conditions and diseases, including cancer, and thus the changes in the expression and function of plasma membrane Ca permeable channels and sodium/calcium exchangers are frequently described in tumorigenesis and tumor development of the upper GI tract, including voltage-gated Ca channels (VGCC), transient receptor potential (TRP) channels, store-operated channels (SOC) and Na /Ca exchanger (NCX). This review will summarize the current knowledge about plasma membrane Ca permeable channels and sodium/calcium exchangers in the upper GI tumors and provide a synopsis of recent advancements on the role and involvement of these channels in upper GI tumors as well as a discussion of the possible strategies to target these channels and exchangers for diagnosis and therapy of the upper GI tumors.