MMP9 and neoplasm: Immunohistochemical staining study indicated that Ku80, p-ERK, p-JNK, MMP-2 and MMP-9 expressions were also decreased in the tumor tissues derived from the miR-623-expressing cells compared with those in the tumors from the NC-transfected A549 cells (Figure 6d; P<0.01; Suplementary Material and Supplementary Figure S7).