OBJECTIVEA fluorescence probe marked with a specific angle protein antibody by using quantum dots QDs605-CK (AE1/AE3) was utilized to detect metastasis and micrometastasis rates of early submandibular lymph node metastatic carcinoma in a nude mouse model. The method was compared with traditional immunohistochemistry (IHC) staining and hematine-eosin (HE) staining to explore a new method for early diagnosis and treatment of tongue squamous cell carcinoma.

METHODSHuman tongue Tca8113 cells were cultured and inoculated in 18 nude mice tongue body tissues (except the midline) to establish submandibular lymph node metastasis in tumor-bearing nude mice models. The nude mice were sacrificed, and the mandibular lymph node was dissected after injecting tumor cells for six weeks. One lymph node was divided into two parts: one was used to create a serial section embedded by paraffin then detected in HE staining and IHC staining; the other was immediately frozen in liquid nitrogen and detected using the fluorescence probe marked with a specific angle protein antibody by using quantum dots. Lymph node metastasis and micrometastases rates were calculated.

RESULTSThe rates of metastasis in the submandibular lymph node via quantum dot immunofluorescence staining, IHC staining, and HE staining showed positive values of 66.7%, 61.1%, and 27.8%, respectively. The micrometastases rates were 38.9% and 33.3% via quantum dot immunofluorescence staining and IHC staining, respectively. The positive rates of detecting lymph nodes metastasis with quantum dot labeled keratin CK (AEl/AE3) immunofluorescence and keratin CK (AE1/AE3) IHC staining were higher than that of conventional HE staining ('=6.379, P<0.05). The two methods showed no statistical difference (chi2 = 0.120, P > 0.05).

CONCLUSIONQuantum dots fluorescent probe marked with the angle protein antibody CK (AE1/ AE3) can precisely locate the submandibular lymph node metastasis tumor cell of the nude mice tongue squamous cell carcinoma, and the emitted red fluorescence showed strong specificity, high resolution, and a clear background. The method could be utilized to detect submandibular lymph node metastasis and micrometastasis of tongue squamous cell carcinoma in nude mice.