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Mutational spectra of PTEN/MMAC1 gene: a tumor suppressor with lipid phosphatase activity
1I. U. Ali, Division of Cancer Prevention, National Cancer Institute, Bethesda, MD 20892-7332, USA. ia1t@nih.gov
Abstract:
PTEN/MMAC1 (phosphatase, tensin homologue/mutated in multiple advanced cancers) is a tumor suppressor protein that has sequence homology with dual-specificity phosphatases, which are capable of dephosphorylating both tyrosine phosphate and serine/threonine phosphate residues on proteins. The in vivo function of PTEN/MMAC1 appears to be dephosphorylation of phosphotidylinositol 3,4, 5-triphosphate. The PTEN/MMAC1 gene is mutated in the germline of patients with rare autosomal dominant cancer syndromes and in subsets of specific cancers. Here we review the mutational spectra of the PTEN/MMAC1 gene in tumors from various tissues, especially endometrium, brain, prostate, and ovary, in which the gene is inactivated very frequently. Germline and somatic mutations in the PTEN/MMAC1 gene occur mostly in the protein coding region and involve the phosphatase domain and poly(A)(6) stretches. Compared with germline alterations found in the PTEN/MMAC1 gene, there is a substantially increased frequency of frameshift mutations in tumors. Glioblastomas and endometrial carcinomas appear to have distinct mutational spectra, probably reflecting differences in the underlying mechanisms of inactivation of the PTEN/MMAC1 gene in the two tissue types. Also, depending on the tissue type, the gene appears to be involved in the initiation or the progression of cancers. Further understanding of PTEN/MMAC1 gene mutations in different tumors and the physiologic consequences of these mutations is likely to open up new therapeutic opportunities for targeting this critical gene.
Insights
The PTEN/MMAC1 gene, a tumor suppressor, frequently mutates in cancers like endometrial and brain tumors. Understanding these PTEN/MMAC1 gene mutations offers potential new cancer therapies.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- PTEN/MMAC1 (phosphatase, tensin homologue/mutated in multiple advanced cancers) is a tumor suppressor protein with dual-specificity phosphatase activity.
- Its in vivo function involves dephosphorylating phosphotidylinositol 3,4, 5-triphosphate.
- The PTEN/MMAC1 gene is implicated in rare autosomal dominant cancer syndromes and various cancers.
Purpose of the Study:
- To review the mutational spectra of the PTEN/MMAC1 gene across different tumor types.
- To analyze the frequency and types of PTEN/MMAC1 gene mutations in specific cancers.
- To explore the implications of PTEN/MMAC1 gene inactivation in cancer initiation and progression.
Main Methods:
- Literature review of PTEN/MMAC1 gene mutations in various cancers.
- Analysis of mutational spectra, focusing on protein coding regions, phosphatase domain, and poly(A)(6) stretches.
- Comparison of germline and somatic mutations, including frameshift mutations.
Main Results:
- The PTEN/MMAC1 gene is frequently inactivated in endometrium, brain, prostate, and ovary tumors.
- Mutations predominantly occur in the protein coding region, affecting the phosphatase domain and poly(A)(6) stretches.
- Frameshift mutations are significantly more common in tumors than in germline alterations.
- Distinct mutational spectra observed in glioblastomas and endometrial carcinomas suggest different inactivation mechanisms.
Conclusions:
- PTEN/MMAC1 gene mutations are critical in the development and progression of various cancers.
- Tissue-specific differences in PTEN/MMAC1 mutational spectra highlight distinct underlying mechanisms.
- Further research into PTEN/MMAC1 gene mutations may reveal novel therapeutic strategies targeting this tumor suppressor.