Antibody‐based screening for hereditary nonpolyposis colorectal carcinoma compared with microsatellite analysis and sequencing

Abstract

BACKGROUNDGermline mutations in the DNA mismatch repair genes, MSH2, MLH1, and others are associated with hereditary nonpolyposis colorectal cancer (HNPCC). Due to the high costs of sequencing, cheaper screening methods are needed to identify HNPCC cases. Ideally, these methods should have a high sensitivity and identify all mutated cases without too many false‐positive cases.METHODSSequencing was compared with microsatellite analysis and immunohistochemistry to detect the presence or absence of the mismatch repair proteins. In the current study, the authors examined 42 patients with colorectal carcinoma of whom 11 met the Amsterdam criteria and 31 were suspected to belong to HNPCC families. Thirty‐five patients were examined by microsatellite analysis, 40 by immunohistochemical staining, and in 31 patients both the MLH1 and MSH2 genes were sequenced.RESULTSNinety‐two percent of patients with germ line mutations were detected by either immunohistochemistry or microsatellite instability, indicating that a combination of these methods may be suitable for HNPCC screening. Microsatellite instability and abnormal immunohistochemical staining were found in 73% of the tumors. Concordance among the three methods was found in 74 % of the tumors.CONCLUSIONSThe authors suggest that immunohistochemistry should be used in combination with microsatellite analysis to prescreen suspected HNPCC patients for the selection of cases where sequencing of the MLH1 and MSH2 mismatch repair genes is indicated. Cancer 2002;95:2422–30. © 2002 American Cancer Society.DOI 10.1002/cncr.10979

Novel strategy for optimal sequential application of clinical criteria, immunohistochemistry and microsatellite analysis in the diagnosis of hereditary nonpolyposis colorectal cancer

“…Further investigations on smaller series confirm the nearly perfect PPV and specificity. 19,36 The PPV and specificity of IHC in our well-defined cohort were 99.1% and 99.6%, respectively. Three cases with loss of protein expression failed to show the expected microsatellite instability.…”

“…19,20,[31][32][33][34][35][36] Clearly, mutation analysis cannot be applied at a large scale and should only be offered to patients with substantial risk of having a deleterious mutation. Also, microsatellite analysis and immunohistochemistry, which have been shown to allow effective enrichment of high-risk patients, are presently not recommended for all cases of colorectal tumors.…”

“…Christensen et al 19 and also Debniak et al 20 proposed a stepwise strategy using IHC in the first place, followed by MSA in case of normal IHC. In contrast, Ponz de Leon et al 21 suggested a strategy using MSA first, followed by IHC in case of abnormal MSA.…”

“…Several investigations have compared the diagnostic performance of MSA and immunohistochemistry (IHC), and screening strategies using both methods sequentially have been proposed. [19][20][21] However, the question of whether either MSA or IHC should be used in the first place, in particular with regard to the total costs of the screening process, has not been addressed in detail so far.…”

Immunohistochemistry versus Microsatellite Instability Testing For Screening Colorectal Cancer Patients at Risk For Hereditary Nonpolyposis Colorectal Cancer Syndrome

“…12,33 Thus, on IHC, these mutant proteins may result in a false-normal staining pattern. Moreover, false-normal staining for MLH1 can occur even with protein-truncating mutations and large in-frame deletions in MLH1, 12,24,27,34 the mechanism for which is unclear.…”