Introduction
General Characteristic of Lynch Syndrome
Patients and Methods
Patient Selection
Immunohistochemistry
DNA Isolation from Paraffin-Embedded Tissue Samples and Peripheral Blood of Lynch Syndrome Patients
Microsatellite Analysis
Sequencing of hMSH2 and hMLH1 Genes
Testing Large Genomic Deletions
MLH1 Promoter Methylation Assay
Detection of BRAF V600E Mutation
Results
Patients Identified Based on Questionnaires
Year | Questionnaires were filled | Suspect patients | Amsterdam II positive | Bethesda positive |
---|---|---|---|---|
2011 | 222 | 19 | 6 | 13 |
2012 | 213 | 14 | 5 | 9 |
2013 | 206 | 12 | 2 | 10 |
2014 | 119 | 15 | 4 | 11 |
Summary | 760 | 60 | 17 | 43 |
Results of Immunohistochemistry and Testing for Microsatellite Instability Analysis
Year | Number of patients | IHC (±) *1 | Microsatellite status | Mutation found (yes/no) |
---|---|---|---|---|
2011 | 6 | – | 4 MSI-H, 2 MSI-L | Yes (2 mutation), *2 |
6 | – | 6 MSS | No | |
4 | + | 4 MSS | No DNA analysis performed | |
2012 | 4 | – | 2 MSI-H, 2 MSI-L | No, *3 |
2 | – | 2 MSS | No | |
1 | + | 1 MSI-H | No | |
6 | + | 6 MSS | No DNA analysis performed | |
2013 | 2 | – | 2 MSI-H | Yes (2 mutation, 1 hypermethylation of hMLH-1 gene) |
1 | + | 1 MSI-H | No | |
8 | + | 8 MSS | No DNA analysis performed | |
2014 | 2 | – | 1 MSI-H, 1 MSI-L | Yes (1 mutation, 1 hypermethylation of hMLH-1 gene) |
3 | – | 3 MSS | No | |
1 | + | 1 MSI-H | No | |
5 | + | 5 MSS | No DNA analysis performed | |
Summary | 51 | 25+, 26- | 12 MSI-H, 5 MSI-L, 34 MSS | 5 mutations found |
Identified Sequence Variants in the MMR Genes
Sex | Age at diagnosis | Amsterdam II | Bethesda | MSI | hMLH1 promoter hypermethylation | Type of gene mutation | Type of the mutation | Mutation | |
---|---|---|---|---|---|---|---|---|---|
1 | F | 44 | no | yes | H | no | MLH1 | Probably Founder | c.143A > C; p.Q48P |
2 | M | 40 | no | yes | H | no | MLH1 | New mutation | c.901insC; p.Q301Pfs5* |
3 | M | 43 | no | yes | H | no | MSH2 | Probably Founder | c.2038C > T; p.R680X |
4 | M | 32 | yes | no | H | no | EPCAM | Mutation | del.ex.8–9-3-kb downstream EPCAM |
5 | M | 43 | no | yes | H | yes | No mutation hMLH1 hypermethylation | – | |
6 | F | 30 | yes | no | H | yes | MSH2 | New mutation with hMLH1 hypermethylation | c.2366_2367del, c.2370_2375del; p.A789Vfs6* |