Role of cyclins D1 and D3 in vestibular schwannoma

Background: Vestibular schwannomas in younger patients have been observed to be larger in size and grow more quickly. Objective: This study aimed to evaluate the expression of three important cell cycle proteins, cyclin D-1, cyclin D-3 and Ki-67, in vestibular schwannoma patients separated into two age groups: 40 years or >40 years. Method: Immunohistochemical detection of cyclin D-1, cyclin D-3 and Ki-67 was undertaken in 180 surgically resected vestibular schwannomas. Results: The proliferation index of vestibular schwannomas was statistically higher in the 40 years age group compared to that in the >40 years age group (mean of 4.52 vs 3.27, respectively; p=0.01). Overexpression of cyclin D-1 and cyclin D-3 was found in 68 per cent and 44 per cent of tumours, respectively. Conclusion: There was an increased Ki-67 proliferation index in the younger age group that appears to correlate with clinical behaviour. Vestibular schwannomas in both age groups show increased expression of cyclin D-1 and cyclin D-3.