Cyclin D1 protein tissue detection in laryngeal cancer.

Cyclin D1 (CCND1) is a set of periodic regulatory proteins that is believed to govern cell cycle transit from G1 into S phase. Overexpression of CCND1 leads to abnormal cellular proliferation which underlies processes of tumorigenesis; CCND1 can thus function as a cooperative oncogene in cell transformation. In the present study we investigate the immunohistochemical expression of CCND1 in a well-documented series of 58 laryngeal squamous cell carcinomas (LSCC) and search for statistical associations between CCND1 index and various clinicopathological parameters including several immunomarkers' expression as well as patients' disease-free survival. Tissue sections from archival paraffin blocks were stained using the avidin-biotin-peroxidase complex method; the H-295 rabbit polyclonal antibody was applied at dilution of 1:150. The percentage of CCND1 immunoreactive tumor cells for each tumor was counted by an image analysis system. CCND1 staining was confined to cell nuclei and, in the examined samples, ranged from undetectable (i.e. 0% of tumor cells, n = 6) to the majority of tumor cells (i.e. 89% of tumor cells) with mean value: 15.73%. In tumor adjacent, non invasive lesions, strong CCND1 staining was noticed in areas with cellular atypia. In cases with nodal metastases, no change in CCND1 expression in the nodal metastases compared with the primary tumors was observed. p53 protein accumulation in malignant cells was positively linked with CCND1 index (Mann-Whitney U: 205.5, p = 0.034). CCND1 expression appears to be an early event in processes of tumorigenesis and tumor progression in some LSCC. Apart from p53 protein accumulation, CCND1 immunohistochemical expression does not seem to correlate with nodal metastasis, disease recurrence or any other clinicopathological prognostic indicator.