Initially, aquaporins (AQPs) were identified as membrane channels facilitating water transport. However, their role extends beyond water homeostasis, influencing cell migration, proliferation, and adhesion—processes closely linked to tumor development and progression. These functions are not dependent only on water flow but also on the transport of small, uncharged molecules such as glycerol, H2O2, urea, NO, and CO2. Particularly, the controlled passage of glycerol and H2O2 can modulate key signaling pathways, altering cellular metabolic and signaling processes. Our previous research revealed new insights into AQPs in cancer. Unexpectedly, AQP3 and AQP5 were detected in the nuclei of cancer cells. AQP3 was also shown to regulate the PI3K/Akt signaling pathway, its expression was increased by an NRF2 activator, and both AQP3 and NRF2 expression were influenced by glucose levels. Based on these findings, we aim to determine whether nuclear localization of AQPs is a tumor-specific feature and whether they can interact with transcription factors. Additionally, we will investigate how glucose regulates aquaporin transcription, define the signaling pathways involved, and assess its impact on therapy response. Furthermore, our clinical data show that AQP3 and AQP5 expression increases in both cancer and stromal cells following immuno- and chemotherapy. Thus, we will examine how aquaporin expression and related signaling pathways change after single and multiple doses of therapeutic agents. Finally, we will validate our in vitro findings in clinical samples. By identifying a common pattern of AQP regulation in cancer, this project aims to establish AQPs as potential biomarkers for therapy selection, offering new perspectives for personalized treatment strategies.