Keratins 6, 13 and 19. Differential expression in squamous cell carcinoma of the head and neck

One hundred forty-one head and neck squamous cell carcinomas were analyzed for keratin (K) 6, 13 and 19. Staining was evaluated by light microscopy (with or without grading) and image analyzer and expressed as a percentage of positive versus all tumor surface (PSA). Both techniques rendered strongly correlated results. Strong expression was noted in 108 carcinomas (76.1%) for K6, in 18 (12.7%) for K19 and in 21 (14.8%) for K13 (P = .001). One hundred thirty-six (96%) tumors were positive for K6, and their PSA ranged from 0.6% to 48.8%; K19, 48 cases (0.2-44%); K13, 59 (0.2-38.1%). Expression of K6 was related to differentiation. K19 was expressed mainly in moderately and poorly differentiated tumors, and K13 was manifest more in well-differentiated carcinomas or in keratinized areas of less-differentiated ones. Nineteen (13.38%) tumors were positive for both K13 and K19. K19 thus was related to tumor progression and K13 to differentiation. There was no correlation with tumor site or TNM category.