PKF118–310 is a potent inhibitor of the interaction between TCF4 (transcription factor 4) and β-catenin (CTNNB1) [91] and has shown growth inhibitory effects in cell line models of prostate cancer [92], osteosarcoma [93], hepatocellular carcinoma [94], and a mouse model of breast cancer [95], but effects on GBM have not been reported. Here, TCF4 is linked to breast cancer.