INCREASED EXPRESSION OF CYTOKERATINS CK8 AND CK19 IS ASSOCIATED WITH HEAD AND NECK CARCINOGENESIS

Malignant transformation is often associated with alterations in the e xpression of normal differentiation markers, which may serve as interm ediate end points in carcinogensis and cancer prevention. To identify early changes in differentiation markers during head and neck cancer d evelopment, we examined the expression of cytokeratins (CK1, CK8, CK13 , and CK19) and involucrin by immunohistochemical methods in surgical specimens from 29 head and neck squamous cell carcinoma patients that included, in addition to carcinoma, adjacent dysplastic lesions (17 ca ses), hyperplastic lesions (21 cases), and adjacent histologically nor mal tissues (15 cases) and in specimens from 31 subjects with premalig nant oral lesions (e.g., oral leukoplakia) without cancer. CK13 and in volucrin were detected in all specimens from the cancer patients, and no differences in their expression were found among the different hist opathological group. CK8 was detected in only 2.7% (1 of 36) of adjace nt normal and hyperplastic tissues but in 58.8% (10 of 17) and 75.9% ( 22 of 29) of dysplastic and carcinoma tissues. The corresponding figur es for CK19 expression in adjacent normal, hyperplastic, dysplastic, a nd carcinoma tissues were 13.3, 70, 71.4, and 82.1%, respectively. The expression of CK1 was not related to the progression from normal to m alignant. In the leukoplakia lesions, CK8, CK13, CK19 and involucrin w ere detected in 13.8, 100, 74.2, and 100% of the specimens, respective ly. These results demonstrate that CK19 expression increases in hyperp lastic lesions and continues to be expressed in dysplastic and maligna nt lesions, whereas CK8 expression is low in adjacent normal and hyper plastic tissues and increases only in dysplastic and malignant lesions . Thus, CK19 and CK8 could be markers of sequential premalignant chang es in head and neck carcinogenesis.