NRP1 and neoplasm: Therefore, it can be speculated that adding LKB1 back to tumor cells triggers complex changes in the tumor microenvironment involving NOX1, ROS, and neuropilin-1 that impact on VEGF/VEGFR-2 signaling and angiogenesis with negative rebounds on tumor growth that largely exceed the modest effects on tumor cell proliferation, which can be detected in vitro.