Recent studies have Identified that much antigens and Lewis X (Lex)-related antigens behave like oncodevelopmental tumor-asnoclated antigens in several human adenocarcino-mas. However, the expression of these antigens In pharyn-geal and latyngeal squamous cell carcinomas (SCC) and in the precursor lesion is not fully elucidated yet. In the present study, the expression of mucin core protein antigens associated with the MUC1 gene product (DF3 antigen, mammary-type apomucin) and the MUC2 gene product (intestinal-MRP antigen, Intestinal-type apomucin) much carbohydrate antigens that are associated with the earliest steps in mucin glycosylation (Tn, sialyl-Tn and T), and Lex -related antigens (Lex, Leγ and slayl Lex-1) In biopsy or resected specimens from 26 normal squamous epithelia (NSE), 49 dysplastic squamous epithelia (DSE) and 51 SCC were examined. The DF3 antigen was not expressed In NSE (0%), whereas it was expressed in 20 DSE (41%) and in 31 SCC (61%). The intestinal-MRP antigen showed no expression in NSE, DSE or SCC. The Tn antigen showed no expression in NSE, but showed low expression rates In DSE (14%) and in SCC (16%). The sialyl-Tn and T antigens were expressed in NSE, as well as in DSE and SCC. The T antigen expression increased with progression from NSE to DSE to SCC, while the sialyl-Tn antigen did not show such a tendency. Any of the three Lex-related antigens showed no characteristic expression in DSE and SCC. In the eight antigens examined, only DF3 antigen was an effective marker for DSE and SCC in the pharyngeal and laryngeal region. Cytoplasmic expression of DF3 and slalyl- Tn antigens were more frequently seen In SCC than in DSE, and might be useful to differentiate SCC from DSE.