OBJECTIVE To assess the signifi cance of sentinel lymph node biopsy (SLNB), serial section and cytokeratin immunohistochemical staining in the diagnosis and staging of Stage-cN0 oral squamous cell carcinoma (OSCC). METHODS A blue stain, 99mTc-dextran SPECT lymphoscintigrapgy and intraoperative γ-ray probes were used to examine the sentinel nodes in 31 cases with Stage-cN0 oral cancer. The H&E staining and a cytokeratin AE1/ AE3 immunohistochemistry (IHC) assessment, with serial sections, were conducted to provide results obtained from a routine pathological examination of lymph nodes. The value of the routine pathological examination of the sentinel lymph node (SLN), serial sections and IHC determination for cervical lymph node metastasis of Stage-cN0 OSCC was appraised. RESULTS A total of 45, 55 and 51 SLNs were examined in 25 (80%), 31 (100%) and 30 (96.5%) of the cases, by using the blue stain, γ-ray probes, and SPECT lymphoscintigraphy, respectively. The average SLNs found in each case of the groups was 1.4 (1 to 3) and there were 1,302 non-NSLNs. Six positive SLN metastases were detected by routine pathological examination, among which 1 case was found to be an accompanied positive metas-tasis of non-SLN. One positive SLN metastasis was found after examination of serial sections plus routine H&E staining and 2 were detected using serial sections plus AE3 immunohistochemical staining methods. No positive NSLNs were found in the study. CONCLUSION In order to make more progress in accurate SLNB diagnosis, serial sections and IHC (AE1/AE3) methods can be used for examination of the micrometastases which are diffi cult to identify by routine pathological sections and H&E staining. OBJECTIVE To assess the signifi cance of sentinel lymph node biopsy (SLNB), serial section and cytokeratin immunohistochemical staining in the diagnosis and staging of Stage-cN0 oral squamous cell carcinoma (OSCC). METHODS A blue stain, 99mTc-dextran SPECT lymphoscintigrapgy and intraoperative γ-ray probes were used to examine the sentinel nodes in 31 cases with Stage-cN0 oral cancer. The H & E staining and a cytokeratin AE1 / AE3 immunohistochemistry (IHC) assessment, with serial sections, were conducted to provide results obtained from a routine pathological The value of the routine pathological examination of the sentinel lymph node (SLN), serial sections and IHC determination for cervical lymph node metastasis of Stage-cN0 OSCC was appraised. RESULTS A total of 45, 55 and 51 SLNs were examined in 25 (80%), 31 (100%) and 30 (96.5%) of the cases by by the blue stain, γ-ray probes, and SPECT lymphoscintigraphy, respectively. The average SLNs found in eac h case of the groups was 1.4 (1 to 3) and there were 1,302 non-NSLNs. Six positive SLN metastases were detected by routine pathological examination, among which 1 case was found to be an anomaly metas-tasis of non-SLN. One positive SLN metastasis was found after examination of the serial sections plus routine H & E staining and 2 were detected using serial sections plus AE3 immunohistochemical staining methods. No positive NSLNs were found in the study. CONCLUSION In order to make more progress in accurate SLNB diagnosis, serial sections and IHC (AE1 / AE3) methods can be used for examination of the micrometastases which are diffi cult to identify by routine pathological sections and H & E staining.