DJ-1 is elevated in prostate cancer and primary lung cancer compared with that in adjacent non-cancerous tissues (6,7); furthermore, its expression is positively correlated with the probability of recurrence in patients with non-small cell

DJ-1, a novel mitogen-dependent oncogene, has an important role in the progression of human malignancies, whereas tumor suppressor phosphatase and tensin homolog (PTEN) is known to control a variety of processes associated with cell survival, proliferation and invasion. DJ-1 overexpression was reported to be negatively correlated with PTEN expression in tumor tissues of patients with laryngeal squamous cell carcinoma (LSCC). In the present study, the effect of DJ-1 on PTEN in laryngeal cancer cells was investigated by transfecting DJ‐1‐specific small interfering (si)RNA into Hep-2 and SNU-899 cells. Cell survival and cell proliferative and invasive capacity were then evaluated. The results showed that siRNA targeting of DJ-1 effectively upregulated PTEN expression, resulting in enhanced cell death as well as decreased proliferation and invasion of Hep-2 and SNU-899 cells. The results of the present study indicated, for the first time, to the best of our knowledge, that DJ-1-induced PTEN downregulation is associated with proliferative and invasive activity of laryngeal cancer cells. The DJ-1 gene may have an important role in the tumorigenesis of LSCC.