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Clinical implication of altered expression of Mad1 protein in human breast carcinoma
1Department of Surgery, Inje University Sanggye Paik Hospital, Seoul, South Korea.
Background:
Mad1 protein is known to repress Myc target genes and antagonize Myc function. The authors undertook this study to investigate the clinical implication of Mad1 expression in human breast carcinoma.
Methods:
The authors performed immunohistochemical assays for Mad1 and Myc proteins in human breast carcinoma, along with tissues from normal breast and benign diseases. The data from protein assays were analyzed in terms of the clinical and biologic characteristics of the patients.
Results:
Of 66 patients with invasive ductal carcinoma, Mad1 expression was detected in 22 (33. 3%). Intensity and area of Mad1 expression significantly decreased in DCIS and invasive cancers, whereas high levels of Mad1 expression were persistent in benign breast lesions. Mad1 expression was significantly reduced in poorly differentiated tumors (P < 0.001). Expression of Mad1 was not associated with tumor size, lymph node status, or stage of disease. The authors did not observe any correlation between S-phase and expression status of Myc or Mad1. Mad1 expression was closely linked to differentiation of the cancer cells and inversely correlated with Myc expression (P = 0.042). In survival analysis, Mad1 was a significant factor in predicting recurrence of the disease, but not overall survival after CMF chemotherapy.
Conclusions:
In human breast carcinoma cells, expression of Mad1 seems to be down-regulated, whereas expression of Myc is amplified. Altered expression of Mad1 may play a role in the malignant transformation of human mammary epithelial cells and represent an aggressive phenotype in human breast carcinoma.
Insights
Mad1 protein expression decreases in breast cancer, particularly in poorly differentiated tumors. Reduced Mad1 correlates with Myc amplification and predicts disease recurrence, suggesting a role in aggressive breast carcinoma.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Research
Background:
- Mad1 protein antagonizes Myc function by repressing Myc target genes.
- Understanding Mad1's role in breast cancer is crucial due to its interaction with Myc.
Purpose of the Study:
- To investigate the clinical implications of Mad1 protein expression in human breast carcinoma.
- To analyze the relationship between Mad1 expression and clinicobiological features of breast cancer.
Main Methods:
- Immunohistochemical assays were performed to detect Mad1 and Myc protein expression.
- Analysis included tissues from normal breast, benign lesions, and invasive ductal carcinoma.
- Data were correlated with clinical and biological characteristics of 66 patients.
Main Results:
- Mad1 expression was detected in 33.3% of invasive ductal carcinomas and decreased significantly in DCIS and invasive cancers.
- Reduced Mad1 expression was associated with poorly differentiated tumors (P < 0.001) and inversely correlated with Myc expression (P = 0.042).
- Mad1 expression was a significant predictor of disease recurrence but not overall survival post-CMF chemotherapy.
Conclusions:
- Mad1 expression is down-regulated in human breast carcinoma, contrasting with Myc amplification.
- Altered Mad1 expression may contribute to malignant transformation and indicate an aggressive phenotype in breast cancer.
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