Application Of Flow Cytometry To Detection Of Occult Metastasis In Cervical Lymph Nodes Of Oral Squamous Cell Carcinoma

ObjectiveTo use flow cytometry to detect the cervical lymph nodes occult metastasis of oral squamous cell carcinoma, and compare the result between flow cytometry and semi-continuous section HE staining, then approach the significance of this technology. Carry out whether are there correlation between the occult metastasis and the clinical and pathological factors of oral squamous cell carcinoma cases, and to provide relative information to the clinical therapy.Materials and Methods1. Clinical data and specimenAll the cervical lymph nodes of oral squamous cell carcinoma patients were collected, those routine pathological examination result was negative, and stored the specimen in—70℃. Bigger lymph nodes (maximum diameter≥1.0cm )were split in the long axis, half were detected by the flow cytometry, and 400μm spacing semi-continuous section HE staining examination was carried on the other half. Smaller lymph nodes(maximum diameter < 1.0cm) were detected by the flow cytometry.2. Flow cytometryTo make the lymph nodes become unicell suspension by the net kneading method, indirect immunofluorescence staining was carried out with CK14 monoclonal antibody (second antibody marked by fluorescein), marking the metastasized endepidermis elements in the lymph nodes. The PI staining was used to separate cell subgroups according to cell cycle. If the double fluorescence positive cells are more than 0.1%, the lymph node was definite as positive lymph node.3. Semi-continuous section HE stainingThe other half lymph nodes were imbedded by paraffin, and section 4μm thick was cut in every 400μm spacing, hematoxylin eosin staining was carried, then the sections were observed by two pathological doctors independently.Results1. The positive rate of all the cervical lymph nodes detected by flow cytometry is 3.2% (15/470).2. The positive rate of occult metastasis of bigger lymph nodes detected by flow cytometry and HE staining are 21.3% and 6.6% respectively, which has statistical significance (x~2=7.11, P <0.01).3. There is no relationship between occult metastasis of lymph nodes and clinical tumor staging, pathological grading, and original tumor location (P>0.05).Conclusions1. Flow cytometry can detect more positive lymph nodes occult metastasis, and has significant difference with semi-continuous section HE staining, so it can be used as a method to detect cervical lymph nodes occult metastasis of oral squamous cell carcinoma.2. There is no relationship between occult metastasis and original tumor location, pathological grading, and clinical tumor staging.