Multiplex PCR (MPCR) Screening Can Detect Small Intragenic p53 Deletion and Insertion Mutations
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Updated: Jan 29, 2026
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Published on: August 23, 2024
1Molecular Biology Laboratory, Department of Obstetrics and Gynecology, University of Ulm, Ulm, Germany.
Abstract:
Mutations of the p53 tumor suppressor gene are the most common alterations associated with malignancy identified so far. Inactivation of the p53 gene contributes to loss of a cell-cycle check point at the G1-S boundary and to genetic instability of the cell eventually allowing cells to replicate in an uncontrolled fashion (1). Inactivating p53 mutations have frequently been identified in many different forms of cancer including more than 50% of ovarian cancers (2,3). The type and location of p53 mutations occurring in human tumors are nonrandom. In a compilation of more than 4200 p53 mutations in human cancers by Soussi et al., 50% of the mutations were missense mutations, 37% frameshift mutations, and 13% nonsense mutations (4). Small intragenic deletions and insertions have gained little attention in the analyses of the p53 gene in human tumors (5,6). However, a review that compiled 740 p53 mutations from a wide variety of cancers showed that 10% of the mutations were either deletions or insertions (7). Insertions were mostly flanked by short direct repeats of up to 14 basepairs (bp). Deletions of up to 37 bp often occurred in areas of sequence repeats. Such structural changes may be explained by a slipped mispairing mechanism during DNA replication (7).
Insights
Mutations in the p53 tumor suppressor gene are common in cancers, leading to uncontrolled cell growth. Small deletions and insertions in the p53 gene, often caused by DNA replication errors, are frequently observed in tumors.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Mutations in the p53 tumor suppressor gene are prevalent in human malignancies.
- p53 gene inactivation disrupts cell-cycle checkpoints and promotes genetic instability, contributing to uncontrolled cell proliferation.
- Over 50% of ovarian cancers exhibit inactivating p53 mutations.
Purpose of the Study:
- To analyze the types and locations of p53 gene mutations in human tumors.
- To investigate the frequency and characteristics of small intragenic deletions and insertions in the p53 gene.
- To explore potential mechanisms underlying structural changes in p53 mutations.
Main Methods:
- Compilation and analysis of a large dataset of p53 mutations from human cancers (over 4200 mutations).
- Review of existing literature on p53 mutations, focusing on deletions and insertions (740 mutations).
- Examination of mutation patterns, including missense, frameshift, nonsense mutations, deletions, and insertions.
Main Results:
- Missense mutations constitute 50% of p53 alterations, followed by frameshift (37%) and nonsense (13%) mutations.
- Small intragenic deletions and insertions account for approximately 10% of all p53 mutations.
- Insertions are often flanked by short direct repeats, and deletions occur in repeat regions, suggesting a slipped mispairing mechanism.
Conclusions:
- p53 gene mutations are a common hallmark of cancer, with diverse mutation types.
- Small deletions and insertions represent a significant subset of p53 mutations and warrant further attention.
- The characteristics of these structural variations suggest DNA replication errors as a likely underlying mechanism.
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