Sentinel lymph node biopsy and immunohistochemistry increase the detection rate of micrometastasis, improving the accuracy of pathologic staging. These methods can be applied in the diagnosis and differential diagnosis of tumors, with anti-keratin antibodies used to determine the epithelial nature of the tumor. Keratin is a type of intermediate microfilament; keratin-positive tumors include cancer, mesothelioma, and most reproductive cell tumors, while keratin-negative tumors include the majority of sarcomas, malignant lymphomas, and malignant melanomas. Depending on the cell differentiation stage, there are differences in the expression of keratin in epithelial cells, so although there are various anti-keratin antibodies, no single antibody can recognize all subtypes of keratin and epithelial types.
CKv is a basic cytokeratin; the anti-CK7 antibody can be used as a marker for adenocarcinoma and transitional cell carcinoma, seen in most glandular epithelium and TCC. CK20 expression varies significantly among different tumor types; anti-CK20 antibody staining is positive in colorectal cancer, biliary tract adenocarcinoma, pancreatic cancer, ovarian mucinous adenocarcinoma, and transitional cell carcinoma, while most other tumors are negative. The anti-CKAE1 tenant is a 4:1 mixture of anti-AE1 and anti-AE3, forming a widely specific human cytokeratin antibody that reacts with stratified squamous epithelium, highly proliferative angular cells, and simple epithelial reactions in internal organs.
The results of this study show that anti-CK7 and anti-CKAE1 tenant are sensitive indicators for detecting sentinel lymph node tumor metastasis, whereas the sensitivity of anti-CK20 for breast cancer epithelial cells should not be used for detecting breast cancer micrometastasis. There are cases where metastatic tumor cells stained by anti-CKv and anti-CKAE1 tenant were tested positive in corresponding parts, with 13 m slices, only one case showing anti-CK20-positive reaction, even when apparent shifts have been found in lesions, the application of anti-CK20 remains negative. In this study, the results of the three types of keratin staining are in good agreement. Considering the additional inspection costs, it does not currently recommend using a two or three staining combination for parallel testing. Whether to select parallel tests for expression in different pathological types depends on further research, as the sample size of different keratins in breast cancer lymph node metastasis in this study is too small. If there are differences, as well as other tumor metastasis detection results, further study is still needed.