Table 1

- Molecular pathology of colorectal cancer syndromes from Saudi patients.

SyndromesGermline alterationsMolecular methodologySample sizeReferences
Lynch syndromePMS2 c.1376C>G, p.S459X, MLH1 c.1652A>C, p. N551T MSH2 c.2262-2267 delTTCTAC, p.T756-Y757 del MSH2 c.1226_1227delAG MSH2 c.1964.delT, p. V655fs MSH2 c.289C>T, Q97* MSH6 c.3475insT, p. Y1159fs MSH6 c.3475insTMMR protein by IHC, MSI, and BRAF mutation testing and deep sequencing2.2% of all CRC (N=1207)19,20
Lynch syndromeMSH2 c.737A>T, p.K246I MSH2 c. 2262_2267del, p.S755_T756del MSH2 c.367-? __1276+? Del MSH2 c.2089T>C, p.C697R MSH2 c. 2038C>T, p.R680* MLH1 c.62C>T, p.A21V MLH1 c.1961C>T, p.P654L MLH1 c.677G>A, p.R226Q MLH1 c.454-?_545+?delMMR protein by IHC, MSI, BRAF mutation testing, MLPA, deep sequencing, and Sanger sequencing7.2% of all CRC (N=284)21
Lynch syndromeDeletion of chromosomal regions: 2p21-2p16.3 (MSH2, MSH6, and EPCAM) 3p23-3p14.2 (MLH1) 7p22.1 (PMS2) 1p34.1-1p33 (MUTYH)Whole genome comparative genomic hybridization arrayN=12 (LS patients)24
FAP syndromePMS2 c.1376C>G, p.S459XWESOne case report19
  • FAP: familial adenomatous polyposis, MMR: mismatch repair, IHC: immunohistochemistry, MSI: microsatellite instability, BRAF: B-Raf, MLPA: multiplex ligation probe amplification, WES: whole-exome sequencing, CRC: colorectal cancer, LS: Lynch syndrome