Worldwide there are more than 273,000 deaths from cervical cancer each year and it accounts for 9% of female cancer deaths. Various alterations are indispensable for the development of this tumor in addition to the human papilloma virus infection. The global incidence rate of primary malignant brain tumors is 3.6 /100,000 person-year in males and 2.5 /100,000 person-year in females. The tumor suppressor gene PTEN on chromosome 10q23.3 was recently identified and found to be inactivated by mutated or epigenetic changes in several different types of human cancers and cancer cell lines. PTEN methylation occurs frequently in cervical and glioblastoma cancer cells and may be associated with focal less of PTEN Expression. Possible reasons for discrepancies of gene expression include differences in the biological effect of specific PTEN mutation. PTEN methylation and mutation of PTEN expression that suggest that mutation and methylation in PTEN play a significant role in the tumorogenesis of cervical cancer and glioblastoma cancer cells. This study might also indicate the utility of this gene is the prognostic marker or its importance in its therapeutic potential.