The clinical relevance of Ki-67 expression in laryngeal squamous cell carcinoma

The aim of this study was to determine the prognostic value of Ki-67 immunostaining in patients affected by laryngeal squamous cell carcinoma. A systematic review was carried out in a tertiary university referral center. An appropriate string was run on PubMed to retrieve articles dealing with Ki-67 immunohistochemical staining and laryngeal squamous cell carcinoma. A double cross-check was performed on citations and full-text articles by two investigators independently to review all manuscripts and perform a comprehensive quality assessment. Of 85 abstracts identified, 18 articles were included. These studies reported on 1,342 patients with histological confirmed diagnosis of laryngeal squamous cell carcinoma. Most studies showed a statistical association between Ki-67 immunohistochemical expression and at least one of the clinical and histopathological parameters considered by the authors. Overall the studies analyzed suggested that the tumoral proliferative index was statistically connected respectively with T stage (2/18), N stage (4/18), grading (6/18), disease-free survival (10/18) and overall survival (4/18). Our review strongly suggests that immunohistochemical staining of Ki-67 correlates with tumoral aggressiveness and worse prognosis in patients affected by laryngeal squamous cell carcinoma. Further high-quality prospective studies should be carried out to confirm our finding and determine the eventual differences between cancers of specific laryngeal subsites.