EPCAM deletion analysis followed by MSH2 methylation testing of the tumor is a fast low-cost procedure that can be used to identify mutations that cause LS.
We previously showed that constitutional 3' end deletions of EPCAM can cause Lynch syndrome through epigenetic silencing of MSH2 in EPCAM-expressing tissues, resulting in tissue-specific MSH2 deficiency.
Recent studies have shown that some Lynch syndrome cases are due to 3' EPCAM/TACSTD1 deletions that subsequently lead to MSH2 promoter hypermethylation.
Members of Family R and Family A, all with the same EPCAM deletion, predominantly presented with CRC but no LS-associated endometrial cancer, confirming findings seen in other, smaller, LS families with EPCAM mutations.
We systematically analysed non-tumorous mucosa from carriers of a Lynch syndrome mutation (set 1: ten patients) and control patients without Lynch syndrome (set 1: nine patients) for MMR protein expression (MLH1, MSH2, and EPCAM) with immunohistochemistry.
Our study's aim was to explore EPCAM expression in colorectal carcinomas of MSH2-associated LS cases to evaluate the usefulness of EPCAM protein expression in the algorithm approach to LS population screening.
Lynch syndrome is the most common inherited CRC syndrome and is associated with mutations in DNA mismatch repair genes, mainly MLH1 and MSH2 but also MSH6, PMS2, and EPCAM.
Larger numbers of Lynch syndrome families and screening of the two additional predisposition genes, PMS2 and EPCAM, are needed in order to decipher the full spectrum of mutations associated with Lynch syndrome predisposition in Cyprus.
Using data from the Colon Cancer Family Registry, we compared the proportion of childhood cancers (diagnosed before 18 years of age) in the first-, second-, and third-degree relatives of 781 probands with a pathogenic mutation in one of the MMR genes; MLH1 (n = 275), MSH2 (n = 342), MSH6 (n = 99), or PMS2 (n = 55) or in EPCAM (n = 10) (Lynch syndrome families), with that of 5073 probands with MMR-deficient colorectal cancer (non-Lynch syndrome families).
EPCAM-CL can be used to screen for EPCAM deletion-induced Lynch syndrome-associated CRC, whereas EPCAM-PL can be used as an indicator of tumor aggressiveness and poor prognosis in CRC.
Germline deletion of the 3' portion of the Epithelial Cell Adhesion Molecule (EPCAM) gene located 5' upstream of MutS Homolog 2 (MSH2) is a novel mechanism for its inactivation in Lynch syndrome.
The ultimate diagnosis of Lynch syndrome requires documentation of mutation within one of the four MMR genes (MLH1, PMS2, MSH2 and MSH6) or EPCAM, currently achieved by comprehensive sequencing analysis of germline DNA.
Lynch syndrome is a hereditary cancer syndrome associated with high risks of colorectal and endometrial cancer that is caused by pathogenic variants in the mismatch repair genes (MLH1, MSH2, MSH6, PMS2, EPCAM).