Hence, considering the importance of TP53, PTEN, and CDKN2A genetic alterations in different proposals of initiation, progression, and classification of gliomas, the aim of this study was to analyze the occurrence of allelic deletions in these genes, as well as to perform a screening of TP53 and PTEN gene mutations in 69 samples of gliomas. The gene discussed is PTEN; the disease is central nervous system cancer.