Expression Of Telomerase Reverse Transcriptase And Its Relationship With Expression Of C-myc In Laryngeal Squamous Cell Carcinomas

Background and ObjectionRecent research has demonstrated that the activation and up - regulation of telomerase is a key step in the pathogenesis of laryngeal squamous cell carcinomas (LSCC). The activity of telomerase is mostly determined by the expression of telomerase catalytic sub - unit ( hTERT) , which is thought as a rate - limiting determinant of the enzymatic activity. Though the mechanism of hTERT activation is still unclear. Several studies have shown that over - expression of c -myc gene may be associated with hTERT activation. However hTERT expression is regulated by c - myc in the development of laryngeal squamous cell carcinoma is still unclear and we have not found related reports about that yet.Materials and Methods1. Patients and samples; thirty nine specimens were taken from 39 LSCC patients undergoing surgical resection at our hospital from 2003 to 2004. And 10 specimens of vocal cord polyps were taken to control.2. Methods; the protein - expression level of hTERT and c - myc genes were detected by Elivision immunohistochemical assays respectively.3. Stastic analysis; All the data were tested by chi square test for fourfold x Fisher s exact test and spearman rank correlation test respectively.Results1. The positive rate of hTERT protein expression in 39 surgically resected LSCC specimens was 84.6% (33/39) ,and that in 10 vocal cord polyps was 0 (0/10). Statistical tests showed that the hTERT protein expression was significantly higher in LSCC than that in vocal cord polyps. ( P <0.01)2. The positive rate of c - Myc protein expression in 39 surgically resected LSCC specimens was 82. 1% (32/39) , and that in 10 vocal cord polyps was 10% (1/10). Statistical tests showed that the c - Myc protein expression was significantly higher in LSCC than that in vocal cord polyps. ( P <0. 01)3. Spearman rank correlation analysis revealed that the expression of c -Myc protein was great significantly related to that of hTERT protein (correlation coefficient r, =0. 541, P <0.01).4. No statistically association was observed among the frequency of hTERT expression and TNM stages, degree of differentiation or lymph nodes metastases. (P>0.05)DiscussionHuman telomerase contains three major components, RNA component ( hTR) , telomerase - associated protein ( TP1) and catalytic subunit ( hTERT). Several studies have demonstrated that hTERT expression is a rate - limiting determinant of enzymatic activity of human telomerase and that up — regulation of hTERT expression may play a critical role in human carcinogenesis.In this study we found that the positive rate of hTERT protein expression in LSCC was 84.6% (33/39). Statistical tests showed that the hTERT protein expression was significantly higher in LSCC than that in vocal cord polyps. This shows that as a new tumor marker,hTERT may be employed in clinical diagnosis of LSCC in the future. We also compared hTERT expression of LSCC with pathological characteristics clinically. The statistical results show that no association was observed among the frequency of hTERT expression and TNM stages, de-...