Related Experiment Video
Updated: Jul 16, 2026
09:37
Defining Gene Functions in Tumorigenesis by Ex vivo Ablation of Floxed Alleles in Malignant Peripheral Nerve Sheath Tumor Cells
Published on: August 25, 2021
RB1 and TP53 pathways in radiation-induced sarcomas.
N Gonin-Laurent1, N S Hadj-Hamou, N Vogt
1Institut Curie, Centre de Recherche, Paris, France.
Oncogene
|March 21, 2007
Summary
Tumor suppressor genes TP53 and RB1 are frequently inactivated in radiation-induced sarcomas. Both genes are crucial for sarcoma development, especially in patients with a predisposition to retinoblastoma.
Area of Science:
- Oncology
- Genetics
- Cancer Biology
Background:
- Radiation-induced sarcomas are rare but aggressive tumors.
- Tumor suppressor genes TP53 and RB1 play critical roles in preventing cancer.
- Understanding the genetic alterations in these genes is vital for developing targeted therapies.
Purpose of the Study:
- To investigate the roles of TP53 and RB1 genes in radiation-induced sarcomas.
- To analyze the genetic alterations in TP53, RB1, and their regulatory genes (INK4a, ARF, MDM2, MDMX).
- To determine the interplay between TP53 and RB1 pathways in sarcoma development.
Main Methods:
- Analysis of 36 post-radiotherapy radiation-induced sarcomas.
- Genetic analysis of TP53, RB1, INK4a, ARF, MDM2, and MDMX genes.
- Detection of point mutations and chromosomal losses.
Main Results:
- Frequent genetic inactivation of RB1 and/or TP53 observed in sarcomas.
- Germline RB1 mutations predisposed patients to retinoblastoma and radiation-induced sarcomas.
- TP53 showed radiation-induced somatic mutations, suggesting an early role in radio-sarcomagenesis.
- RB1 and TP53 were biallelically co-inactivated in predisposed sarcomas.
- In non-predisposed sarcomas, TP53 was biallelically inactivated, while RB1 retained at least one wild-type allele.
- TP53 pathway inactivation occurred via genetic lesions, not ARF/MDM2/MDMX pathway activation.
Conclusions:
- TP53 and RB1 are critical tumor suppressors in radiation-induced sarcomas.
- Genetic alterations in TP53 and RB1 pathways are key drivers of radio-sarcomagenesis.
- Tissue- and etiology-specific interactions between TP53 and RB1 pathways influence tumorigenesis.
Related Concept Videos
02:23Abnormal Proliferation
Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
03:03mTOR Signaling and Cancer Progression
The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
The mTOR pathway or the...
01:20The Retinoblastoma Gene
Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
01:31The Intrinsic Apoptotic Pathway
Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
01:23Negative Regulator Molecules
Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
01:12Loss of Tumor Suppressor Gene Functions
Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...