Consistently, the western blotting analysis also demonstrated that BL-PDT downregulated the expression of Bcl-2, pro-caspase 3, pro-caspase 9, and PARP and upregulated the expression of Bax, cleaved-caspase 9, and cleaved-PARP in GC cells (Fig. 4G, H and Additional file 1: Fig. S3E-F). This evidence concerns the gene CASP9 and gastric cancer.