Related Experiment Video
Updated: Jul 2, 2026
Analysis of Cell Cycle Position in Mammalian Cells
Published on: January 21, 2012
Evidence of a tumour suppressive function of E2F1 gene in human breast cancer
1Institute of Cancer Genetics and Pharmacogenomics, Brunel University, Uxbridge, Middlesex, UK.
Background:
The E2F family of transcription factors are key regulators of genes involved in cell cycle progression, cell fate determination, DNA damage repair and apoptosis. E2F1 is unique in that it contributes both to the control of cellular proliferation and cellular death. Furthermore, unlike other E2Fs, E2F1 responds to various cellular stresses. This study aimed to examine the level of mRNA expression of E2F1 gene in normal and malignant breast tissue and correlate the level of expression to tumour stage.
Materials And Methods:
One hundred and twenty-seven breast cancer tissue and 33 normal tissues were analyzed. Levels of transcription of E2F1 were determined using real-time quantitative PCR, normalized against CK19. Levels of expression were analyzed against TNM stage, nodal involvement, tumour grade and distant metastasis.
Results:
The levels of E2F1 mRNA were lower in malignant tissues. They declined further with increasing TNM stage. This became statistically significant when TNM stages 3 and 4 were compared to TNM stages 1 and 2 disease (TNM1 vs. TNM3 p = 0.032; TNM1 vs. TNM4 p = 0.032; TNM2 vs. TNM3 p = .019; TNM2 vs. TNM4 p = 0.021). The levels of E2F1 also fell with increasing tumour grade, when comparing grade 2 and 3 with grade 1, however, the differences were not statistically significant.
Conclusion:
These results are highly suggestive of the role of E2F1 as a tumour suppressive gene in human breast cancer.
Insights
E2F1 mRNA levels are lower in breast cancer tissues and decrease with advanced tumor stage, suggesting E2F1 acts as a tumor suppressor gene in breast cancer.
Area of Science:
- Molecular Biology
- Genetics
- Oncology
Background:
- E2F transcription factors regulate cell cycle, fate, DNA repair, and apoptosis.
- E2F1 uniquely controls proliferation and cell death, responding to cellular stresses.
- This study investigates E2F1 mRNA expression in breast tissue and its correlation with tumor stage.
Purpose of the Study:
- To quantify E2F1 mRNA expression in normal and malignant breast tissues.
- To correlate E2F1 expression levels with clinicopathological parameters such as TNM stage, nodal involvement, tumor grade, and distant metastasis.
Main Methods:
- Analysis of 127 breast cancer and 33 normal tissue samples.
- Real-time quantitative PCR used to determine E2F1 mRNA transcription levels, normalized against CK19.
- Statistical analysis of E2F1 expression against TNM stage, nodal status, tumor grade, and metastasis.
Main Results:
- E2F1 mRNA levels were significantly lower in malignant breast tissues compared to normal tissues.
- A statistically significant decline in E2F1 mRNA levels was observed with increasing TNM stage (stages 3 & 4 vs. 1 & 2).
- E2F1 levels showed a trend of decreasing with higher tumor grade, though not statistically significant.
Conclusions:
- The findings strongly suggest E2F1 functions as a tumor suppressor gene in human breast cancer.
- Reduced E2F1 expression is associated with more advanced stages of breast cancer.
- Further research into E2F1's role could inform breast cancer therapeutic strategies.
Related Concept Videos
01:20The Retinoblastoma Gene
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,...
02:23Abnormal Proliferation
02:38Mitogens and the Cell Cycle
01:12Loss of Tumor Suppressor Gene Functions
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...
01:12Loss of Tumor Suppressor Gene Functions
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...
01:05Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...