Study Of Cyclin G1 And G2 Protein Expression In Laryngeal Squamous Cell Carcinoma

ObjectiveThe purpose of this study is to investigate the expression of cyclinG1 and cyclinG2 in the laryngeal squamous cell carcinoma and their surrounding normal laryngeal mucosa, to get its role in pathogenesis of LSCC, to investigate the relationship between cyclinG1 cyclinG2 and LSCC and their surrounding normal laryngeal mucosa and to indicate the relationship between the expression of cyclinG1 cyclinG2 and the pathological grade, clinical stage and the anatomic type of primary LSCC.Materials and Methods1. MaterialsThe 52 LSCC and their surrounding normal laryngeal mucosa came from the first hospital affiliated to the China Medical University,all diagnosis were made by its pathology.The surrounding normal laryngeal mucosa was used as the control group. All of the patients had not received either chemotherapy or radiotherapy before surgery.2. S-P immunohistochemistry methodBy which we got the expression patterns of cyclinG1 and cyclinG2.All procedures followed the product illustration.Nucleus and /or plasma stained as positive.We used Pearson X~2 test to analysis.ResultCyclinG1 protein expression in cell nucleus ,while cyclinG2 was found in plasma with S-P immunohistochemistry method. The cyclinG1 expression positive rate in LSCC is 82.69%(43/52),in their surrounding normal laryngeal mucosa is 30.77% (16/52);the positive rate of cyclinG2 expression in LSCC is 21.15%(ll/52) and in their surrounding normal laryngeal mucosa is 61.54%(32/52).We used x~2 test analysis and got the significant differences between both cyclinG1 and cyclinG2 in LSCC and their surrounding normal laryngeal mucosa .Cyclin G1 expressed higher in LSCC and cyclinG2 expressed lower in LSCC.There was a correlation between expression of cyclinG1 , cyclinG2 and the pathological grade and the clinical stage of primary LSCC. While there was no correlation between expression of cyclinG1 cyclinG2 and the anatomic type of primary LSCC.DiscussionCyclinG1 is located mainly in nucleus, expressed at high levels in skeletal muscle ,ovary, kidney and colon,whose expression is induced by the damage of DNA and depends on p53. Smith found that cyclinG1 promoted the cell proliferation with the enlargement and increasing of colonies in vitro culture through the transfection experiment in which they conducted cyclinG1 cDNA into cells of colon cancer and normal blastofibrocytes of human being.Our test showed that cyclinG1 expressed highly in LSCC,the differences had the statistic meaning. Too many cyclinG1 expression can inhibit the apopsis of the cells ,thus leads to endless increasing of the tumor cells.Horne reported their work of cyclinG2 clone first. Bates' farther research showed that both of the mRNA expression of cyclinG1 and cyclinG2 can be induced by DNA-damage drug actinomycin-D, which has the p53 dependency for cyclinG1 but the p53 independency for cyclinG2. When the growth inhibition of B cell or the cell cycle is arrest, the transcription level of cyclinG2 is up-regulated. Wykoff found that a series of target genes of transgene inducing expression included cyclinG2 through re-conducting the VHL cancer-suppressing gene into renal cancer cells with VHL gene defect. In this test we got that cyclinG2 expression decreased in LSCC , it is much more likely for cyclinG2 to have the negative regulating function to the cell proliferation.Conclusion1. The result of our research indicates that cyclinG1 is the positive regulating factor and cyclinG2 is the negative regulating factor in the LSCC cell proliferation.2. With the rising of the pathological grade and the clinical stage of LSCC , cyclinG1 expressed more highly,while cyclinG2 lower. There was no correlation between expression of cyclinG1 cyclinG2 and the anatomic type of primary LSCC.