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Updated: Oct 22, 2025

Yeast As a Chassis for Developing Functional Assays to Study Human P53
Published on: August 4, 2019
TP53 isoform junction reads based analysis in malignant and normal contexts
Suleyman Vural1,2, Lun-Ching Chang3, Laura M Yee1
1National Cancer Institute, Division of Cancer Treatment and Diagnosis, Biometric Research Program, Rockville, MD, 20850, USA.
Abstract:
TP53 is one of the most frequently altered genes in cancer; it can be inactivated by a number of different mechanisms. NM_000546.6 (ENST00000269305.9) is by far the predominant TP53 isoform, however a few other alternative isoforms have been described to be expressed at much lower levels. To better understand patterns of TP53 alternative isoforms expression in cancer and normal samples we performed exon-exon junction reads based analysis of TP53 isoforms using RNA-seq data from The Cancer Genome Atlas (TCGA), Cancer Cell Line Encyclopedia (CCLE), and Genotype-Tissue Expression (GTEx) project. TP53 C-terminal alternative isoforms have abolished or severely decreased tumor suppressor activity, and therefore, an increase in fraction of TP53 C-terminal alternative isoforms may be expected in tumors with wild type TP53. Despite our expectation that there would be increase of fraction of TP53 C-terminal alternative isoforms, we observed no substantial increase in fraction of TP53 C-terminal alternative isoforms in TCGA tumors and CCLE cancer cell lines with wild type TP53, likely indicating that TP53 C-terminal alternative isoforms expression cannot be reliably selected for during tumor progression.
Insights
The TP53 gene
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- The TP53 gene is frequently altered in cancer, with NM_000546.6 being the predominant isoform.
- Alternative TP53 isoforms exist at lower expression levels and may have altered tumor suppressor activity.
Purpose of the Study:
- To investigate the expression patterns of TP53 alternative isoforms in cancer and normal tissues.
- To determine if TP53 C-terminal alternative isoforms increase in tumors with wild-type TP53.
Main Methods:
- Analysis of exon-exon junction reads from RNA-seq data.
- Utilized datasets from The Cancer Genome Atlas (TCGA), Cancer Cell Line Encyclopedia (CCLE), and Genotype-Tissue Expression (GTEx) projects.
Main Results:
- Observed no substantial increase in the fraction of TP53 C-terminal alternative isoforms in TCGA tumors and CCLE cell lines with wild-type TP53.
- Contrary to expectations, TP53 C-terminal alternative isoforms did not significantly increase in tumors with wild-type TP53.
Conclusions:
- TP53 C-terminal alternative isoforms, which have reduced tumor suppressor activity, are not significantly selected for during tumor progression.
- The expression of TP53 alternative isoforms may not be a reliable indicator for tumor progression in wild-type TP53 cancers.
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