Objective   To explore the clinical significance of the expression of KAI1/CD82 in the tissues of laryngeal squamous cell carcinoma (LSCC)

laryngeal squamous intraepithelial neoplasia (SIN) Ⅰ to Ⅲ and normal laryngeal mucosa.    Methods   Envision immunohistochemistry was used to detect the expression of KAI1/CD82 gene in 26 specimens of LSCC

34 specimens of laryngeal SIN Ⅰ to Ⅲ

and 10 specimens of normal laryngeal mucosa. Correlation of the expression of KAI1/CD82 gene to clinicopathologic data were statistically analyzed.    Results   The rates of negative

weak

moderate

and strong expression of KAI1/CD82 in LSCC were 57.7% (15/26)

26.9% (7/26)

15.4%(4/26)

and 0%(0/26)

respectively

significantly lower than those in normal laryngeal mucosa and laryngeal SIN (P=0.000 5). Expression of KAI1/CD82 in LSCC had no correlation with clinical stage

tumor histological grade and lymph node metastasis (P0.05). There was no correlation between the expression of KAI1/CD82 in laryngeal SINⅠ~Ⅲ and histological grade (P0.05) .    Conclusion   The change of KAI1/CD82 expression is an early event in tumorigenesis of LSCC. KAI1/CD82 may play a significant role from laryngeal SIN to LSCC. Its downregulation may be considered as a potential marker for tumor metastasis.