| Laryngeal squamous cell carcinoma (LSCC) is a common malignant neoplasm in Otolaryngology and increasing incidence has been observed. The complex molecular mechanisms in the malignant transformation and progression of laryngeal carcinoma have still not been well understood, like other tumors. Recent studies have proved that dysregulation of the genes controlling apoptosis may contribute to the process of tumorigenesis by reducing the rate of cell death and allowing the accumulation of other genetic defects. Apoptosis , or Programmed cell death (PCD), is an automatic cell death process which is different from necrosis completely. This process plays an important role in thecourse of embryo development, differentiation, mature and death. Apoptosis is controlled by many genes, P53, Bcl-2 and Bax are genes that have been more heavily studied in the research of apoptosis. Normal P53 protein is assayed to be checkpoints in G1 phase of cell cycle and exerts its function by leading to cycle arrest or apoptosis as a result of DNA damaging events. The mutant protein lacks this property. Bcl-2 protein is thought to reduce the apoptotic capacity, whereas the Bax protein may induce apoptosis. Many reports suggest that both occurrence and development of many kinds of tumors are associated with apoptosis. Until recently, the joint detection of P53, Bcl-2 Bax oncoprotein and the relation among the expression of P53,Bcl-2 and Bax in laryngeal squamous cell carcinomas have not been reported. In order to investigate the correlation between the expression of P53,Bd-2, Bax in laryngeal carcinogenesis and the clinicopathological parameters, the immunohistochemical S-P method was used to examine the expression of the three kinds of proteins in 50 cases of laryngeal squamous cell carcinomas with 20 samples of laryngeal normal mucosa (LNM) and 38 samples laryngeal atypical hyperplasia (LAH) as controls in the study.Rusults1. The positive immunostaining of three oncoproteins appeard brow granular distribution. P53 oncoprotein was localized inthe nuclei. Bcl-2 oncoprotein was mainly expressed in cytoplasm of cells and a small part of cell membranes were stained, there was no expression in the cell nuclei and stroma. Bax oncoprotein was expressed in cytoplasm and cell membrane and there were a little expression in stroma and nuclei.2. In laryngeal normal mucosa, laryngeal atypical hyperplasia and laryngeal squamous cell carcinoma, the positive immunostaining rates of P53 protein were 0.0% (0/20X 52.6% (20/38) and 62.0% (31/50) respectively, there was statistical significance among three groups ( x2=22.122 P <0.01 ); Bcl-2 protein, 5.0% (1/20), 76.3% (29/38) and 50.0% (25/50)respectively, there was statistical significance among three groups ( AT2=26.698 P<0.01); Bax protein, 75.0% ( 15/20 )> 50.0% (19/38) and 64.0% (32/50) respectively , there was no statistical significance among three groups ( *2=3.773 P>0.05)03. In G1,G2 and G3 laryngeal squamous cell carcinomas, Bcl-2 positive expression were 11.1% (l/9)> 44.0% (11/25) and 81.3% ( 13/16 ) respectively , there was statistical significance among three groups ( x 2=12.054 P < 0.01). With the presence of lymph-node metastasis and without the presence of lymph-node metastasis, Bcl-2 immunoreactivity rates were 66.7% (18/27) and 30.4%( 7/23 ) respectively, there was statistical significancebetween two groups( x2=6.522 P<0.05), suggesting that Over-expression of Bcl-2 is significantly associated with histological grading and lymph-node metastases, while there was no statistical significance in the expression of P53 and Bax (P>0.05).4. There was no significant correlation was detectable between age, sex, smoking habit, clinical type, clinical stage, T stage, the anatomical site of tumor and the expression of P53,Bcl-2,Bax (P>0.05).5 In laryngeal atypical hyperplasia and laryngeal squamous cell carcinoma, the reverse relation was found between P53 and Bcl-2 expressio...
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