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Effect of cyclin D1 and associated proteins on proliferation of esophageal squamous cell carcinoma
1Department of Surgery II, Osaka University, Medical School, Suita, Osaka 565, Japan.
Abstract:
Cyclin D1, which functionally competes with the tumor suppressor genes retinoblastoma (Rb) and p16INK4, is widely recognized as an oncogene. P27KIP1, which inhibits the cyclin D1-CDK4 complex, is also a putative tumor suppressor gene. In order to evaluate the regulatory interaction of these molecules, a retrospective series of tissues from 66 patients with esophageal squamous cell carcinoma was evaluated immunohistochemically for the expressions of cyclin D1, Rb, p16INK4 and p27KIP1. The expressions of these molecules were correlated with the proliferation cell nuclear antigen (PCNA) index as an indicator of cell proliferation. Cyclin D1 was overexpressed (++) in 28 cases (42%), Rb was lost (-) in 19 cases (24%), p16INK4 was lost (-) in 37 cases (56%) and p27KIP1 was lost (-) in 27 cases (41%). Taken together, disorder of at least one or more of these molecules was observed in 62 cases (92%). Expression of cyclin D1 and p16INK4 was negatively correlated (p<0.03), while expression of cyclin D1 and p27KIP1 was positively correlated (p<0.0004). We found strong overall correlation between expression of cyclin D1 and the PCNA index (p<0.0001), however expression of p16INK4 and p27KIP1 was significantly correlated with the PCNA index in tumors devoid of cyclin D1 overexpression (p<0.03 and p<0.02 respectively). Thus, it was found that cyclin D1 plays a major role and closely related to abnormal cell proliferation in esophageal cancer, however assessment of p16INK4 and p27KIP1 status, particularly in tumors devoid of cyclin D1 overexpression, is necessary for comprehensive evaluation of cancer cell proliferation. Furthermore, expression of cyclin D1 is correlated with that of p16INK4 and p27KIP1 in squamous cell carcinoma of the esophagus.
Insights
Cyclin D1 is a key oncogene in esophageal cancer, driving abnormal cell proliferation. Assessing p16INK4 and p27KIP1 is crucial for a full understanding of cancer progression, especially when cyclin D1 is not overexpressed.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Research
Background:
- Cyclin D1 is an oncogene that competes with tumor suppressors Rb and p16INK4.
- P27KIP1 inhibits the cyclin D1-CDK4 complex and is a potential tumor suppressor.
- Understanding the interplay of these molecules is vital in esophageal squamous cell carcinoma.
Purpose of the Study:
- To evaluate the regulatory interactions between cyclin D1, Rb, p16INK4, and p27KIP1.
- To correlate their expressions with cell proliferation markers in esophageal squamous cell carcinoma.
- To elucidate the role of these proteins in esophageal cancer development.
Main Methods:
- Retrospective analysis of 66 esophageal squamous cell carcinoma tissue samples.
- Immunohistochemical evaluation of cyclin D1, Rb, p16INK4, and p27KIP1 expression.
- Correlation analysis with the proliferation cell nuclear antigen (PCNA) index.
Main Results:
- Disorders in at least one molecule were observed in 92% of cases.
- Cyclin D1 overexpression occurred in 42% of patients.
- Negative correlation between cyclin D1 and p16INK4; positive correlation between cyclin D1 and p27KIP1.
- Cyclin D1 strongly correlated with PCNA index; p16INK4 and p27KIP1 correlated with PCNA in tumors without cyclin D1 overexpression.
Conclusions:
- Cyclin D1 significantly contributes to abnormal cell proliferation in esophageal cancer.
- Assessing p16INK4 and p27KIP1 is important for comprehensive proliferation evaluation, especially in cyclin D1-negative tumors.
- Cyclin D1, p16INK4, and p27KIP1 expressions are interconnected in esophageal squamous cell carcinoma.