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Molecular genetic analysis of TGF beta1 in breast cancer
M R Cardillo1, E Yap, G Castagna
1Histopatology Unit, University La Sapienza of Rome, Italy.
Abstract:
Conflicting data suggest that TGF-beta1 can either inhibit or promote the progression of breast cancer. To determine the biological role of TGF beta1 in mammary carcinoma, in this study we examined the gene structure, expression and localization of TGF-beta1 using paraffin-embedded samples from 32 (27 IDC, 1 ILC, 1 DCIS, 1 ADH) breast lesions. Gene mutations in the region coding for the active protein were investigated by PCR-SSCP of exons 5, 6, and 7. mRNA -TGF-beta1 expression and distribution was examined by NISH using cDNA probes generated by RT-PCR and immunohistochemistry. We detected two mutations in exon 6 TGF-beta1 from IDC; and TGF beta1 mRNA and proteins in 28 (87%) of the tumors. Invasive breast carcinomas had more intense TGF-beta1 activity than CIS and than normal tissue adjacent to tumor. TGF beta1 mRNA and proteins were higher at the edge of the tumor than in the center and were also higher in less differentiated breast neoplasms. TGF-beta1 mRNA transcription and protein levels did not correlate either with TGF-beta1 exon 6 mutation or type and grade of differentiation of breast tumors. These observations suggest that TGF beta1 mutations in breast neoplasms might cause loss or inactivation of the growth inhibitory effects of TGF-beta1. They also support the proposed role of TGF-beta1 in the pathogenesis of breast cancer.
Insights
Transforming growth factor-beta1 (TGF-beta1) mutations in breast cancer may inactivate its growth inhibitory effects. This study found higher TGF-beta1 activity in invasive carcinomas, suggesting its role in breast cancer pathogenesis.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Conflicting data exist on the role of Transforming Growth Factor-beta1 (TGF-beta1) in breast cancer progression, with evidence suggesting both inhibitory and promoting effects.
- Understanding the specific role of TGF-beta1 in mammary carcinoma is crucial for targeted therapeutic strategies.
Purpose of the Study:
- To investigate the gene structure, expression, and localization of TGF-beta1 in breast lesions.
- To determine the correlation between TGF-beta1 mutations, expression levels, and clinicopathological features of breast cancer.
Main Methods:
- Analysis of gene structure, including mutations in exons 5, 6, and 7 of TGF-beta1, using PCR-SSCP.
- Examination of TGF-beta1 mRNA expression and distribution via non-isotopic in situ hybridization (NISH).
- Immunohistochemistry was employed to assess TGF-beta1 protein levels and localization.
Main Results:
- Two mutations in exon 6 of TGF-beta1 were identified in invasive ductal carcinomas (IDC).
- TGF-beta1 mRNA and protein were detected in 87% of the breast tumors studied.
- Higher TGF-beta1 activity was observed in invasive breast carcinomas compared to carcinoma in situ (CIS) and adjacent normal tissue.
- TGF-beta1 expression was more intense at the tumor periphery than in the center and higher in less differentiated tumors.
- No correlation was found between TGF-beta1 exon 6 mutations and mRNA/protein levels, nor with tumor type or differentiation grade.
Conclusions:
- TGF-beta1 mutations in breast neoplasms may lead to the loss or inactivation of its growth-inhibitory functions.
- The findings support a role for TGF-beta1 in the pathogenesis of breast cancer, particularly in invasive stages.
- Altered TGF-beta1 signaling, potentially due to mutations, could contribute to breast cancer progression.