Author/Editor		Volavšek, Metka; Gale, Nina
Title		p53, p21, Rb and cyclin D1 expression in squamous cell carcinoma of the larynx and hypopharynx
Type		članek
Source		In: Gale N, Žargi M, editors. Epithelial tumours of the head and neck. Proceedings of the 31st memorial meeting for professor Janez Plečnik under the auspices of the European society of pathology; 2000 Dec 7-8; Ljubljana. Ljubljana: Faculty of medicine, Institute of pathology,
Publication year		2000
Volume		str. 14-7
Language		eng
Abstract		One of major mechanisms in carcinogenesis is increased cell proliferation: The important checkpoint in progression through the cell cycle is activity of gene p53: Activation of p53 mediates cell cycle, arrest influencing the p21 gene, the cyclin dependent kinase inhibitor. Cyclin D1; negatively affected by the p21, causes the transition of the cell from the quiescent phase into the cell cycle. Another negative regulator of cyclin D1 activity is the Rb protein. The presence and possible interrelation of immunohistochemically detected products of p53, p21; Rb and cyclin D1 genes in 62 squamous cell carcinomas (SCC) of the larynx and hypopharynx were studied. Tissue samples were stained immunohistochemically with antibodies against proteins p53, p21; Rb and cyclin D1. Immne reactions were scored according to the % of nuclear positivity in tumor cells. Inverse correlations were present between cyclin Dl and p21 ( p=0,001), cyclin Dl and Rb (p=0,005), and tumor grade and Rb expression (p=0,002). A positive correlation was present between p21 and Rb expression. There were no correlations with p53 immune reactions. Our results showed alterations in cell cycle control in almost all cases. In tumor cells, both derailment of the apoptotic pathway (through p53) and growth promoting pathway (through overexpression of cyclin Dl) of the cell cycle were present. The correlation between cyclin D1 and p21 (independent of p53) indicates that in tumor cells, p21 expression is not always influenced by gene p53. The correla tion between tumor grade and Rb expression suggests the involvement of possible Rb gene mutations in the development of SCC. Rb mutations, involved in tumorigenesis of many malignant tumors, have not yet been considered important in the pathogenesis of CSS. To confirm this possibility, detailed molecular studies are needed.
Descriptors		LARYNGEAL NEOPLASMS HYPOPHARYNGEAL NEOPLASMS CARCINOMA, SQUAMOUS CELL LARYNGECTOMY PROTEIN P53 PROTO-ONCOGENE PROTEIN P21(RAS) RETINOBLASTOMA PROTEIN CYCLINS