CTSS and central nervous system cancer: Moreover, we built protein–protein interaction network of these proteins and suggested the important role of DNA topoisomerase 2-alpha (TOP2A) in the signal-transduction cascade of tachyplesin I. In conclusion, we propose that tachyplesin I might down-regulate cathepsins in lysosomes and up-regulate TOP2A to inhibit migration and promote apoptosis in glioma, thus contribute to its anti-tumor function.