Based on the results of in vitro cell screening, we next selected one of the most active DNAzyme DT882 for further validation of its activity of down-regulation of bcl-xL expression in a panel of cancer cell lines (PC3, prostate cancer; T24, bladder cancer; A549, lung carcinoma; CNE-1, nasopharyngeal carcinoma; HCT116, colon cancer). The gene discussed is BCL2L1; the disease is cancer.