Objective   To investigate the change of expression of MTAP gene and its linked genes p14, p15 and p16 in patients with non-small cell lung cancer and its clinical significance.

  Methods   Thirty fresh samples of local cancer tissue and its nearby tissue from 15 patients with lung cancer were analyzed for mRNA of MTAP gene and its linked genes p14, p15 and p16 by RT-PCR.

  Results   In 15 tumor samples, 11 (73.3%) were not detected the MTPA expression or the transription level of MTPA mRNA was reduced by more than 5 times; but in nearby tisue samples, the rate of MTPA expression was as high as 93.3%.In addition, the low level of expression in samples from lung adenocarcinoma and from squamous cell carcinoma did not different significantly. But the low expression rate of MTPA in intermediate and poorly differentiated lung cancer was significantly higher than that in well-differentiated cancer. Furthermore, RT-PCR was performed to observe the differentiated cancer. Furthermore, RT-PCR was performed to observe the differences between MTAP gene and its linked genes p14、p15 and p16 for 7 patients with lung cancer. Unexpectedly, it was found that p16 and p14 were expressed athigher level in 3 of 7 tumor samples respectively than in matched normal tissues, while p15 mRNA was deficient in 5 tumor samples.

  Conclusion   The low expression or loss of MTPA gene may be relevant closely to the differentiation degree in lung cancer. The loss of MTPA gene may be independent of p16 gene, which suggested that the low expression or loss of MTPA should be of special biological significant in tumor biology.