Objective: To investigate the expressions of tumor suppressor gene CX26 mRNA and coding protein in laryngeal squamous cell carcinoma, and to explore the relationship between CX26 gene and the biological behaviors of laryngeal squamous cell carcinoma for understanding the tumorigenicity and development of laryngeal squamous cell carcinoma.
Method: Laryngeal carcinoma tissues (studying group), which takeda from the center of tumors and laryngeal normal tissues (control group) takeda at the place of 1.0 cm out of the edge of the tumors, were took from 38 patients with laryngeal squamous cell carcinoma while they were in operation. Semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was used to analyze the expression level of CX26 mRNA, and immunohistochemical staining (frozen section) was used to detect the expression of CX26 protein in laryngeal carcinoma tissues and laryngeal normal tissues of 38 cases, respectively.
Result: mRNA of CX26 gene was all positively expressed in laryngeal carcinoma tissues and laryngeal normal tissues of 38 cases by RT-PCR. However, CX26 mRNA was obviously down-regulated in laryngeal carcinoma tissues than that in laryngeal normal tissues (P < 0.05). Immunohistochemical staining showed CX26 protein was strong-positively expressed in laryngeal normal tissues in 34 cases (89.5%), while it was positively expressed in laryngeal carcinoma tissues in 18 cases (47.4%), and with the location alteration of CX26 protein in laryngeal carcinoma cells. There was significant difference between the expression rate of CX26 protein in laryngeal carcinoma tissues and in laryngeal normal tissues (P < 0.05). Meanwhile, the expression level of CX26 mRNA and the positive-expressed rate of CX26 protein of the laryngeal carcinoma tissues in the advanced stage patients group (III stage and IV stage) were significantly lower than these in the early stage patients group (I and II) (P < 0.05), and it was significantly lower in those who have a cervical lymph node metastasis than those without metastasis. (P < 0.05). Moreover, the expression level of CX26 mRNA and the positive-expressed rate of CX26 protein reduced along with the reduction of pathological differentiation, and there was significant difference among the well-differentiated group, moderately-differentiated group and poorly-differentiated group (P < 0.05).
Conclusion: CX26 gene may play an important role in the pathogenesis and development of laryngeal carcinoma and may be related to its prognosis.