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Clinicopathological Analysis of miRNA Expression in Breast Cancer Tissues by Using miRNA In Situ Hybridization
Published on: June 7, 2016
Smad4-expression is decreased in breast cancer tissues: a retrospective study
Christina H Stuelten1, Miriam B Buck, Juergen Dippon
1Department of Clinical Chemistry, Robert Bosch Hospital, Stuttgart, Germany. chrisstu@mail.nih.gov
Background:
Although transforming growth factor beta (TGF-beta) typically inhibits proliferation of epithelial cells, consistent with a tumor suppressor activity, it paradoxically also exhibits pro-metastatic activity in the later stages of carcinogenesis. Since tumors often display altered TGF-beta signaling, particularly involving the Smad-pathway, we investigated the role of Smad4-expression in breast cancer.
Methods:
Smad4 expression was investigated by immunohistochemistry in formalin-fixed, paraffin-embedded tissue from 197 samples of primary breast cancer obtained between 1986 and 1998. The prognostic value of Smad4-expression was analyzed.
Results:
Smad4 expression was found to be reduced in lobular and ductal breast carcinoma as compared to surrounding uninvolved lobular and ductal breast epithelia (p < 0.001, n = 50). Smad4-expression correlated positively with expression of TGF-beta-receptor I (p < 0.001, n = 197) and TGF-beta-receptor II (p < 0.001, n = 197), but showed no significant correlation with tumor size, metastases, nodal status, histological grade, histological type, or estrogen receptor expression. While not achieving statistical significance, there was a trend towards longer survival times in patients with Smad4 negative tumors.
Conclusion:
According to the suggested role of Smad4 as a tumor suppressor we observed that expression of Smad4 is lower in human breast cancer than in surrounding breast epithelium. However, we also observed a trend towards longer survival times in Smad4-negative patients, indicating the complex role of TGF-beta signaling in tumor progression.
Insights
Smad4 expression is reduced in breast cancer, contradicting its tumor suppressor role. However, Smad4-negative tumors showed a trend towards longer survival, indicating complex TGF-beta signaling in tumor progression.
Area of Science:
- Oncology
- Molecular Biology
- Cell Signaling
Background:
- Transforming growth factor beta (TGF-beta) signaling typically inhibits epithelial cell proliferation, suggesting tumor suppressor activity.
- Paradoxically, TGF-beta can promote metastasis in later cancer stages.
- Altered TGF-beta signaling, particularly the Smad-pathway, is common in tumors.
Purpose of the Study:
- Investigate the role of Smad4 expression in breast cancer.
- Analyze the prognostic value of Smad4 expression in breast carcinoma.
Main Methods:
- Immunohistochemistry was used to assess Smad4 expression in 197 primary breast cancer tissue samples.
- Smad4 expression levels were compared between tumor tissue and surrounding uninvolved breast epithelium.
- Statistical analysis was performed to correlate Smad4 expression with clinicopathological features and patient survival.
Main Results:
- Smad4 expression was significantly reduced in both lobular and ductal breast carcinoma compared to normal breast epithelium.
- Smad4 expression positively correlated with TGF-beta-receptor I and II expression.
- No significant correlation was found between Smad4 expression and tumor size, metastasis, nodal status, grade, type, or estrogen receptor status.
- A trend towards longer survival was observed in patients with Smad4-negative tumors, though not statistically significant.
Conclusions:
- Smad4 expression is downregulated in human breast cancer, consistent with a tumor suppressor role.
- The observed trend of longer survival in Smad4-negative patients suggests a complex, context-dependent role for Smad4 in breast cancer progression.
- Further research is needed to elucidate the intricate mechanisms of TGF-beta signaling in breast cancer development and metastasis.
