OBJECTIVETo explore the correlation between expression of mitogen-activated protein kinase kinase 4 (MKK4) and metastasis of oral squamous cell carcinoma (OSCC).

METHODSExpression levels of MKK4 mRNA and protein were examined in surgically resected oral squamous cell carcinoma specimens and corresponding lymph nodes by semi-quantitative reverse Transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry.

RESULTSThe expression of MKK4 in 48 cases of metastasis of lymph node group was significantly higher than 27 cases of without metastasis of lymph node group in 75 cases of paraffin-embedded OSCC samples (P < 0.05). The expression of MKK4 in 48 cases of metastatic lymph node lesions was higher than 48 cases of primary site of OSCC (P < 0.05). There was no correlation between the expression of MKK4 and primary site, size of tumor, histological grade ( P > 0.05). The expression of MKK4 mRNA in 16 cases of metastasis of lymph node group was significantly higher than 22 cases of without metastasis of lymph node group in 38 cases of fresh OSCC samples (P < 0.01). The expression of MKK4 in 6 cases of matched metastatic lymph node lesions was higher than 16 cases of primary tumour (P < 0.05)

CONCLUSIONThe up-regulation of MKK4 protein and mRNA may be related with the invasion and metastasis of OSCC. MKK4 maybe played a promoting role in the progression and metastasis of OSCC.