Related Experiment Videos
Expression of mdm-2 protein in neoplastic, preneoplastic, and normal bronchial mucosa specimens: comparative study
A Rasidakis1, D Orphanidou, J Kalomenidis
1Department of Respiratory Medicine, Medical School of Athens University, Greece.
Abstract:
Loss of function of the p53 tumor supressor gene is involved in nearly all human cancer. Recently a cellular oncogene product, mdm2, has been shown to bind to p53 and eliminate its ability to function as a transcription factor. mdm2 and p53 immunohistochemical protein expression was studied in tumor tissues, preneoplastic lesions, and normal bronchial mucosa. The specimens were obtained during diagnostic bronchoscopy from 53 patients with lung cancer. In the tumor specimens, p53 nuclear staining was detected in 26 (49%) cases, mdm2 in 11 (20.7%), and simultaneous expression of both proteins in 6 (11.3%) cases. Thirty-five sections with preneoplastic lesions were found in 21 patients. p53 nuclear staining was found in 11 of 35 and mdm2 in 6 of 35 sections. In normal cells, mdm2 positive staining was found in 18 and p53 in 12 specimens. Simultaneous p53 and mdm2 expression was found in 4 specimens. Our results indicate that p53 expression is more frequent than mdm2 expression in lung cancer tissues. Alterations in these proteins are early events and may represent alternative pathways in carcinogenesis.
Insights
p53 tumor suppressor gene loss is common in cancer. This study found p53 expression is more frequent than mdm2 in lung cancer tissues, suggesting alternative cancer development pathways.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Research
Background:
- The p53 tumor suppressor gene is critical in preventing cancer, with its loss of function observed in most human cancers.
- The mdm2 oncogene product interacts with p53, inhibiting its transcriptional factor activity and contributing to oncogenesis.
Purpose of the Study:
- To investigate the immunohistochemical expression of p53 and mdm2 proteins in lung cancer tissues, preneoplastic lesions, and normal bronchial mucosa.
- To determine the prevalence and co-expression patterns of p53 and mdm2 in different stages of lung carcinogenesis.
Main Methods:
- Immunohistochemical analysis of p53 and mdm2 protein expression was performed on 53 lung cancer tumor specimens, 35 preneoplastic lesions, and normal bronchial mucosa samples.
- Specimens were obtained via diagnostic bronchoscopy from patients with lung cancer.
Main Results:
- p53 nuclear staining was observed in 49% of tumor specimens, while mdm2 was detected in 20.7%.
- Simultaneous p53 and mdm2 expression occurred in 11.3% of tumors. In preneoplastic lesions and normal tissues, p53 and mdm2 expression levels varied.
- p53 expression was found to be more frequent than mdm2 expression in lung cancer tissues.
Conclusions:
- Alterations in p53 and mdm2 expression are early events in lung carcinogenesis.
- The distinct expression patterns suggest that dysregulation of p53 and mdm2 may represent alternative molecular pathways in the development of lung cancer.