Detection of Gastric Cancer Micrometastases in Lymph Nodes by Amplification of Keratin 19 mRNA with Reverse Transcriptase‐Polymerase Chain Reaction

Abstract

A sensitive method for the detection of gastric cancer micrometastases in lymph nodes was developed. The method was based on amplification of keratin 19 mRNA by reverse transcriptase‐polymerase chain reaction (RT‐PCR). Keratin 19 RT‐PCR showed that keratin 19 mRNA was expressed in all 12 gastric cancers, but not in any of 20 normal control lymph nodes, indicating that keratin 19 mRNA is a good target of RT‐PCR for the detection of gastric cancer micrometastases in lymph nodes. Serial dilution studies of RNA extracted from gastric cancers against RNA extracted from control lymph nodes demonstrated that the detection sensitivity of the keratin 19 RT‐PCR method was one cancer cell in 103‐105 lymph node cells. Detectability of lymph node metastases was compared between keratin 19 RT‐PCR and conventional histological examination, using 100 lymph nodes obtained from 12 gastric cancer patients. Keratin 19 mRNA was detected in all of the seven lymph nodes which were historically metastasis‐positive. Of the 93 lymph nodes which were histologically metastasisnegative, 79 were found not to express keratin 19 mRNA but 14 were found to express keratin 19 mRNA, indicating that these lymph nodes contained micrometastases which could not be detected by histological examination. These results demonstrate that keratin 19 RT‐PCR is a more sensitive method than histological examination for the detection of gastric micrometastases in lymph nodes.

Overexpression of dopa decarboxylase in peritoneal dissemination of gastric cancer and its potential as a novel marker for the detection of peritoneal micrometastases with real-time RT–PCR

“…However, sometimes side effects occur such as ileus, fever, leukocytopenia and so on, so that it has been necessary to determine the indication for this therapeutic application to avoid such side effects. The extreme sensitivity of RT -PCR makes it possible to diagnose micrometastases on the basis of tissue-specific mRNA expression of tumour cells in peripheral blood, bone marrow, lymph nodes and cerebrospinal fluid Johnson et al, 1995;Maehara et al, 1996;Noguchi et al, 1996;Mori et al, 1998). Recently, the use of rapid quantitative RT -PCR-based screening methods for the detection of micrometastasis from clinical specimens has become standard procedure (Nakanishi et al, 2000;Sato et al, 2001;Oki et al, 2002).…”

Development of a sensitive, specific reverse transcriptase polymerase chain reaction-based assay for epithelial tumour cells in effusions

“…Cytokeratins are one of the most widely utilized molecular markers for the detection of epithelial cancer cells in blood, bone marrow aspirates and lymph nodes by molecular methods (Datta et al, 1994, Schoenfeld et al, 1994Fields et al, 1996;Noguchi et al, 1996aNoguchi et al, , 1996b. In general, the three most primitive keratins, K8, K18 and K19, are expressed by all epithelial cells (Traweek et al, 1993).…”

“…PCRbased methods fall into three categories: (a) methods to detect cancer-specific products or genes such as mutated K-ras genes, which reveal the presence of circulating pancreatic cancer cells (Nomoto et al, 1996); (b) methods to detect expression of genes specific for the tissue of origin of the tumour cell, such as prostatespecific antigen, which indicates the presence of circulating or micrometastatic prostate carcinoma cells (Katz et al, 1994); and (c) methods to detect expression of epithelial cell-specific genes such as cytokeratin 19 (K19), which is indicative of circulating or micrometastatic carcinoma cells (Datta et al, 1994;Schoenfeld et al, 1994;Fields et al, 1996;Noguchi et al, 1996aNoguchi et al, , 1996b. The last approach is not restricted to one or a few tumour types, and is useful for the detection of tumour cells from many, as well as unknown, sites of origin in fluids or tissues.…”

Detection of lymph node micrometastasis in pN0 early gastric cancer: Efficacy of duplex RT-PCR with MUC2 and TFF1 in mucosal cancer

“…Micrometastases that exist at the time of the primary tumor operation are thought to be involved in tumor recurrence (8,9). Carcinoembryonic antigen (CEA) and cytokeratins (CK) have been widely used to detect LMM in gastric and colorectal cancer (7,(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). These CEA and CK assays, however, have high false positive rates (22)(23)(24)(25)(26).…”