To show that expressed and released Laz by S. typhimurium VNP-Laz was cytotoxic and able to induce apoptosis in cancer cell lines, VNP-Laz cells were co-cultured with either breast cancer cells MCF-7, glioblastoma cells LN-229 or U-373 in hypoxic conditions followed by fluorometric assay of caspase 3/7 activity for assessment of apoptosis that is Laz-induced. This evidence concerns the gene CASP3 and breast cancer.