Abstract:
Objective :To investigate the depletion and mutation of the anti-oncogene PTEN in gastric cancer and precancerous lesions.
Methods : Thirty cases of normal gastric mucosa, precancerous lesions and gastric cancer were analyzed for PTEN loss of heterozygosity (LOH) and mutations within the entire coding region of the PTEN gene, DNA from the above group were extracted by the method of saturated sodium chloride, PTEN LOH was detected by PCR-SSCP denaturing PAGE gel electrophoresis and silver staining, PTEN mutation was detected via PCR-SSCP sequencing.
Results : PTEN LOH was found in 10% of atrophic gastritis, 10% of intestinal metaplasia, 13.3% of atypical hyperplasia, 20% of early stage gastric cancer and 33.3% of advanced stage gastric cancer. None of the precancerous lesions and early stage gastric cancer showed PTEN mutations. For the advanced stage gastric cancer, PTEN mutation were found in 10% cases and they were all LOH positive.
Conclusion : LOH of PTEN gene appears in precancerous lesions and the PTEN mutations are restricted to advanced gastric cancer. It is closely correlated to the infiltration and metastasis of gastric cancer.