MTOB (alpha-keto-gamma-Methylthiobutyric acid) is a small molecule inhibitor of the transcriptional co-repressor CtBP, disrupting its oncogenic functions. It has been shown to inhibit cancer cell proliferation and modulate TCF-4/Wnt signaling pathways in both cellular assays and in vivo mouse models, making it a valuable research tool for studying cancer stemness and tumorigenesis.