KRAS and malignant colon neoplasm: Another contributing factor to the different cytotoxic activity of PBT against the two colon cancer cell lines is their differences in terms of epigenetic and genetic features; they possess a different status of the KRAS gene with the HT29 cells harboring the wild type of KRAS, while the HCT116 cells contain a mutated type which enables the activation of the KRAS signaling pathway, thus achieving high oncogenic potential and aggressivity.