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Abnormalities of retinoblastoma gene structure in human lung tumors
S Linardopoulos1, E S Gonos, D A Spandidos
1Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, Athens, Greece.
Abstract:
The retinoblastoma (Rb) gene is associated with the pathogenesis of several types of human cancer, including retinoblastoma, osteosarcoma, soft tissue sarcomas, and lung, breast and bladder carcinomas. Loss of heterozygosity is a common mode in allelic inactivation of Rb and other tumor-suppressor genes. We investigated DNA from 15 human lung tumors for loss of heterozygosity of the Rb locus using a polymerase chain reaction (PCR) based restriction fragment length polymorphism assay. Of informative cases we found loss of heterozygosity in 2 out of 3 squamous cell carcinomas and 1 out of 2 adenocarcinomas of the lung. We also found structural rearrangements in two out of fourteen Hind III digested lung tumors examined at the 5' region of the human Rb gene using Southern blot hybridization analysis. Since these two tumors were classified as stage III it is possible that the alteration of Rb gene is involved in the progression of this type of cancer. Using specific primers for exons 15, 16, 21 and 22 of the Rb gene, we carried out amplification of these exons by polymerase chain reaction. None of these tumors showed a deletion of exons 15, 16, 21 and 22.
Insights
The retinoblastoma (Rb) gene, crucial in tumor suppression, shows alterations in lung cancer. Loss of heterozygosity and structural rearrangements in the Rb gene were observed in some lung tumors, suggesting its role in cancer progression.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- The retinoblastoma (Rb) gene is a critical tumor suppressor involved in various human cancers.
- Loss of heterozygosity (LOH) is a common mechanism for inactivating tumor-suppressor genes like Rb.
- Lung cancer pathogenesis involves genetic alterations, including those affecting tumor suppressor genes.
Purpose of the Study:
- To investigate alterations of the retinoblastoma (Rb) gene in human lung tumors.
- To assess the frequency of loss of heterozygosity (LOH) at the Rb locus in lung cancer.
- To identify structural rearrangements in the Rb gene in lung tumor samples.
Main Methods:
- Polymerase chain reaction (PCR) based restriction fragment length polymorphism (RFLP) assay to detect LOH.
- Southern blot hybridization analysis to examine structural rearrangements at the 5' region of the Rb gene.
- PCR amplification of specific Rb gene exons (15, 16, 21, 22) to check for deletions.
Main Results:
- Loss of heterozygosity (LOH) was detected in 2 out of 3 informative squamous cell carcinomas and 1 out of 2 informative lung adenocarcinomas.
- Structural rearrangements in the 5' region of the Rb gene were found in two Stage III lung tumors using Southern blot analysis.
- No deletions of exons 15, 16, 21, or 22 were identified in the examined lung tumors via PCR.
Conclusions:
- Alterations in the retinoblastoma (Rb) gene, including LOH and structural rearrangements, are present in human lung tumors.
- These Rb gene alterations may play a role in the progression of lung cancer, particularly in advanced stages.
- Further investigation is warranted to fully elucidate the role of the Rb gene in lung tumorigenesis.