The induction of apoptosis was specific to CRC cell lines HCT116, SW480, DLD1, and RKO, but was absent in primary cell lines, implying a tumor-specific effect.70 Another study indicated that heat-killed L. reuteri induced apoptosis through Akt-p53 dependent mitochondrial apoptosis in a MKN1 human gastric cancer cell line.72 Given that non-metabolically active L. reuteri can induce apoptosis in a tumor-specific manner, it is likely that there is a cellular component mediating tumor cell death. This evidence concerns the gene TP53 and neoplasm.