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.