Concordance between MSI and IHC in the Lynch syndrome Tumor Screening Program at Udaondo Hospital, a Gastroenterological public center in Argentina

ANTELO, MARINA; GOLUBICKI, MARIANO; STACH, LUCÍA; CARBALLIDO, MARCELA; MENDEZ, GUILLERMO; ISEAS, SOLEDAD; CABANNE, ANA; CISTERNA, DANIEL; ROCA, ENRIQUE

Auckland

Congreso; International society for gastrointestinal hereditary tumours?InSiGHT - 8th. Biennial Meeting; 2019

International society for gastrointestinal hereditary tumours

Aim: CRC´s tissue testing for MMR deficiency with MSI, MMR IHC, or both, is an effective approach to identify carriers of a germline MMR gene mutation (Lynch syndrome)1 and patients with specific prognostic and therapeutic implications2. Nevertheless, MMR IHC has several advantages over MSI: it is cheaper, it is faster, and it is easier to perform, so it is the technique of choice, especially in institutions like ours with limited economic resources3,4. The objective of this project was to study the concordance between MSI and MMR IHC in CRC´s samples at our institution.Methods: CRC?s from 200 consecutive patients with Amsterdam or Bethesda clinical criteria evaluated during 2016-2017 at the Lynch syndrome Tumor Screening Program (Oncology Section, Udaondo Hospital, Buenos Aires, Argentina) were tested for MMR status with MSI and MMR IHC. Comparison between MSI vs. IHC results was done, and Cohen´s kappa coefficient was calculated to define the accuracy and sensitivity of both assays. Results: the overall agreement (concordance) between both techniques was 90.5% (181/200), with a Cohen´s kappa coefficient of 0.734 (p