Amino acid transporters play an important role in supplying organic nutrient to cells. The expression of L-type arnino acid transporter 1 (LATl) and its subunit 4F2 heavy chain (4F2hc) was evaluated to deterrnine the alterations to these transporters in oral norrnal mucosa (ONM) , oral precancerous lesion (OPL) and oral squamous cell carcinoma (OSCC). Sections from formalin-ftxed, paraffm-embedded S따nples of ONM, OPL or OSCC were exarnined using immunohistochernical staining to detect LATl and 4F2hc proteins. 까le LATl and 4F강lC expression increased progressively from ONM to hypeφ，Iastic and to dysplastic lesions and OSCC. In partiαlar， LATl rnay be a more S야dftc indicator of tumor prog~않sion than 4F2hc. 까le gradually increasing LA Tl and 4F2hc expression detected during the multistep progressive change shows that the protein rnay have an important role in the early stages of multistep oral carcinogenesis. In addition, the specific inhibition of LA Tl and 4F2hc rnight be a new rationale to suppress oral cancer progression.

Nitric oxide (NO) plays a key role in the processes of inflammation and carcinogenesis. Three isoforms of NO 야mthase have been identified: endothelial 띠띠c oxide 와nth앓e (NOS), neuronal NOS, and inducible NOS (이OS). The purpose of this study was to investigate the characteristics of iNOS expression in 7, 12-dimethylbenz[alanthracene (DMBA)-induced hamster buccal pouch carcinogenesis. Sixty three outbred young (6-week-old) male Syrian golden hamsters were randomly divided into three groups: DMBA treated group (n=57) and non-treated (n=3), and mineral-oil treated group (n=3). No iNOS activity could be detected in the untreated or mineral oil-treated pouches. 80th cytoplasmic and nuclear stainings were observed in the DMBA-treated pouch kera띠lCX까es. There were iNOS expression 외so in the strorna1 cells. The mean values of iNOS expression in the epithelium increased gradually from control to dysplastic lesions and more to invasive squ따nous cell carcinoma. πle clifference between iNOS expr'않sion in the normal and that the dysplastic and carcinomatous lesions is statistically significant. The mean values of iNOS expression in the stroma increased gradually from control to dysplastic lesions and more to invasive squamous cell carcinoma. The difference between iNOS expression in the normal and that the carcinomatous lesions is statistica11y si맑， ificant. In conclusion, this study has demonstrated that iNOS is expressed in DMBA-induced hamster pouch carcinomas. πlis finding suggests that iNOS expression may be associated with the development of chemically induced oral carcmomas.