ABSTRACT
<p><b>OBJECTIVE</b>To investigate the expression of full-length spleen tyrosine kinase [SYK (L)] mRNA and protein in human oral squamous cell carcinoma (OSCC) as well as its possible effects on the invasion and metastasis of OSCC.</p><p><b>METHODS</b>The expression of SYK (L) was detected in 27 cases of OSCC tissues and its matched adjacent non-cancerous tissues by real-time quantitative polymerase chain reaction (RT-qPCR), Western blot, and immunohistochemistry. Fourteen cases of normal oral gingival tissues were also analyzed as a normal control.</p><p><b>RESULTS</b>Reduced mRNA and protein expression of SYK (L) in OSCC tissues was observed compared with that in normal oral gingival tissues (P<0.01) and adjacent non-cancerous tissues (P<0.05). SYK(L) expression was significantly associated with lymph-node metastasis (P<0.05).</p><p><b>CONCLUSION</b>SYK(L) is a candidate tumor suppressor for OSCC tissues, and has an inhibitive effect on the initiation, proliferation, and lymph-node metastasis of human OSCC.</p>