Added Value of Combined Gene and Protein Expression of CK20 and CEA in Non—macroscopically Involved Lymph Nodes of Colorectal Cancer

Abstract

A methacarn fixation permits an approach that comprises multiple techniques. In this study the procedure is used to examine 100 mesenteric lymph nodes from patients with colon cancer by means of histology, immunohistochemistry (IHC), and reverse transcriptase polymerase chain reaction (RT-PCR). The evaluated nodes are found to be grossly free of metastases. The combined expression of both messenger RNA (mRNA) and protein is investigated to validate the presence of structural (cytokeratin 20, or CK20) and tumor-specific (carcinoembryonic antigen, or CEA) markers. Histological analysis shows micrometastases on 4 nodes. IHC analysis identifies isolated (CK20 and CEA positive) tumor cells on 14 other nodes. In this group, none of the nodes that are positive for CK20 IHC express the related mRNA. RT-PCR confirms the CEA IHC positivity in 50% of the cases. The double CEA IHC/RT-PCR positivity would have up-staged 33% of the pN0 cases to pN1. This approach offers a technological framework for further studies that aim to validate the clinical significance of protein/mRNA expression of tumor markers in colorectal cancer sentinel lymph nodes.

Prognostic Value of Molecular Detection of Lymph Node Metastases After Curative Resection of Stage II Colon Cancer: A Systematic Pooled Data Analysis

“…18,19 Immunohistochemical methods to stain cytokeratin 20 and carcinoembryonic antigen have been used to identify isolated tumor cells in regional LNs, but their clinical relevance is still debated. [20][21][22] The development of quantitative RT-PCR (RT-qPCR) methods combined with tissue-specific markers offers a remarkable opportunity to quantify occult metastases to define prognostic risk and predict the benefit of adjuvant chemotherapy. 15,23,24 Guanylyl cyclase C (GCC) is a colon-specific marker that is uniquely expressed by apical cells of the gastrointestinal tract and is involved in multiple functions, including water transport, crypt morphology, and suppression of tumorigenesis.…”

Comparing the efficacy of routine HandE staining and cytokeratin immunohistochemical staining in detection of micro-metastasis on serial sections of dye-mapped sentinel lymph nodes in colorectal carcinoma

“…In H&E method, MM was detected in four nodes; in IHC (CK) method, ITCs were reported in 14 nodes; and in RT-PCR method, CEA(Carcinoembriogenic Antigen) positivity was reported in 50 nodes. [ 12 ] Likewise, Lim, using IHC (CK) method, could detect ITCs in 7% of the SLNs. [ 13 ] Kelder, by using IHC method, found 18% of MM/ITCs in SLNs.…”