HNPCC / Lynch syndrome / Non-polyposis colon carcinoma



Hereditary nonpolyposis colorectal cancer (HNPCC; Lynch Syndrome), is a type of inherited cancer of the digestive tract, particularly the colon and rectum. In addition, it increases the risk for numerous other cancers, most likely due to the inherited mutations in DNA repair genes.In the overwhelming majority of HNPCC cases (>80%), germ-line defects in the DNA mismatch repair genes MLH1 and MSH2 are responsible. A significant percentage of these mutations are genomic deletions of one or more exons of the MLH1 and MSH2 genes.


The MLH1 gene contains 19 exons and spans 57 kb on chromosome 3p22.2. The MSH2 gene contains 16 exons and covers 80 kb on chromosome 2p21. The P003-C1 probemix contains probes for each of the 19 exons of the MLH1 gene and for each of the 16 exons of the MSH2 gene. From version B1 onwards, two probes are included for the most 3’ exon of EPCAM (formerly known as TACSTD1), a gene located just upstream of MSH2. Deletions of the most 3’ exon of EPCAM can result in silencing of the MSH2 gene. Finally, 9 reference probes detecting several autosomal locations are included.