Cyclin D1 Gene Numerical Imbalances in Laryngeal Squamous Cell Carcinoma: A Tissue Microarray Grid Based Analysis

Abstract

Background: Deregulation of critical proteins involved in cell cycle stability, such as cyclins, is a frequent genetic event in the development and progression of solid malignancies. Concerning laryngeal squamous cell carcinoma (LSCC), cyclin D1 oncogenic transformation leads to an aberrant protein expression and seems to affect the biological behaviour of the neoplasm. The aim of this study was to determine the correlation of cyclin D1 numerical imbalances with the corresponding protein expression levels in LSCCs. Material and Method: Using tissue microarray (TMA) technology, fifty (n=50) histologically confirmed primary LSSCs were cored at a diameter of 1.5 mm. Immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH) analyses were applied. Concerning the screening process in CISH slides, a novel real-time reference and calibration grid platform was implemented. Results: Protein overexpression was observed in 22/50 (44%) cases; whereas, gene amplification was seen in 13/50 (26%) cases (p=0.02). Combined protein/ gene deregulation was associated with the stage of malignancy (p= 0.0014, p=0.001), whereas overall protein expression was strongly correlated with the grade of tumour (p= 0.001). Conclusion: Cyclin D1 gene amplification led to aberrant protein expression in LSCCs and it was also correlated with an aggressive biological behaviour. To best of our knowledge, this study was the first described grid based CISH analysis under conventional bright field microscopy for detecting gene numerical imbalances while providing a novel and accurate description for screening-mapping process in the entire slide area.<br />