BACKGROUND: P27kip1 -family member of Cyclin Dependent Kinase (CDK) inhibitors- has key position in cell cycle regulation, leading to arrest of cell proliferation. It enables a repair process of DNA damage through inhibition of different CDKs and therefore control the cell cycle by balancing the activity of CDKs. Changes in the level of P27kip1 which can be shown by (immunohistochemistry) can alter the normal progression of the cell cycle and its reduced expression has been shown in some tumors. Cyclin D1 also indirectly promotes cell proliferation by sequestering p21 and P27kip1, leading to the activation of CDK2. The present study aims at investigating the expression of P27kip1 and cyclin D1 proteins in selected benign lesions (pleomorphic adenoma, warthin’s tumor) and mucoepidermoid carcinoma and their possible correlation with clinicopathologic features.
PATIENTS AND METHODS: Clinicopathological features of 50 patients (30 mucoepidermoid carcinoma-10 pleomorphic adenoma, 10 warthin’s tumors), including age, sex and tumor size were obtained from medical records in the period 2009-2013, from files of pathology department, faculty of medicine- Benha University and Egyptian national cancer institute (NCI) and 10 cases of sialoadenitis were taken as control. Grades of cases of mucoepidermoid carcinoma were (18 low grade, 12 intermediate and high grade). Stages (16 cases of stage I,II and 14 cases of stage III, and IV). Immunohistochemical staining with P27kip1 and cyclin D1 was performed for each specimen.
RESULTS: Highly statistical significant difference in P27kip1 expression between PA, warthin’s tumor & MEC. Inverse statistical significant correlation between P27kip1 expression and tumor stage. High inverse statistical significant correlation between P27kip1 expression and histologic grade. Inverse correlation between P27kip1 expression and age, tumor size and nodal status but with no statistical significance. High positive statistical significant correlation between cyclin D1 expression and tumor size, nodal status, stage and histologic grade. Insignificant difference in cyclin D1 expression between PA, warthin’s tumor and MEC. Positive correlation between cyclin D1 expression and patient age but with no statistical significance. Significant difference in cyclin D1 expression between males and females
CONCLUSION: In summary, our results provide evidence that reduced expression of P27kip1 may be involved in initiation, clinical progression and poor prognosis of mucoepidermoid carcinoma patients. Also, our findings indicate that cyclin D1 overexpression may play a pivotal role in the biological behavior of MEC and may provide a strong prognostic implication. |
