N63: Clinical And Molecular Characterization Of Lynch-Like Syndrome

M. D. Picó1, R. Jover2, M. Giner2, M. Alustiza2, J. L. Soto3, A. Castillejo3, A. B. Sánchez4, A. Sánchez5, F. Balaguer5, L. Moreira5, A. Castells5, M. Pellise5, M. Carrillo-Palau6, T. Ramon y Cajal7, G. Llort8, C. Yagüe8, A. Lopez Fernandez9, J. Balmaña9, E. Martinez de Castro10, C. Alvarez11, X. Bessa11, J. Cubiella12, L. Rivas12, D. Rodríguez-Alcalde13, A. Dacal14, M. Herraiz15, C. Garau16, L. Bujanda17, L. Cid18, C. Povés19, M. Garzon20, A. Pizarro20, A. Gomez21, I. Salces22, M. Ponce23, E. Aguirre24, E. Saperas25, V. Piñol26

1 – Gastroenterology, Hospital General Universitario de Elche, Elche, Alicante, Spain. 2 – Gastroenterology, Hospital General Universitario de Alicante, Alicante, Spain. 3 – Genetic. Hospital General Universitario de Elche, Alicante, Spain. 4 – Oncology. Hospital General Universitario de Elche, Alicante, Spain. 5 – Gastroenterology, Hospital Clinic Barcelona, Barcelona, Spain. 6 – Hospital Universitario de Canarias, Tenerife, Spain. 7 – Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. 8 – Corporació Sanitària Parc Taulí. Sonsorci Sanitari Terrasa, Sabadell – Terrasa , Spain. 9 – Hospital Vall d’Hebron, Barcelona, Barcelona, Spain. 10 – Hospital Universitario Marques de Valdecilla, Santander, Spain. 11 – Hospital del Mar, Barcelona, Barcelona, Spain. 12 – Complexo Universitario Hospitalario de Ourense, Ourense, Spain. 13 – Hospital Universitario de Móstoles, Mostoles, Spain. 14 – Hospital Universitario Lucus Aungusti, Lugo, Spain. 15 – Clinica Universitaria de Navarra, Navarra, Spain. 16 – Hospital de Son Llàtzer, Palma de Mallorca, Spain. 17 – Hospital de Donostia, Donostia, Spain. 18 – Hospital Álvaro Cunqueiro de Vigo, Vigo, Spain. 19 – Hospital clínico de San Carlos, Madrid, Spain. 20 – Hospital Universitario Virgen del Rocío, Sevilla, Spain. 21 – Hospital Universitario de Guadalajara, Guadalajara, Spain. 22 – Hospital 12 de Octubre, Madrid, Spain. 23 – Hospital Universitari i Politecnic de la Fe, Valencia, Spain. 24 – Hospital Quiron de Zaragoza, Zaragoza, Spain. 25 – Hospital General de Catalunya, Barcelona, Spain. 26 – Hospital Josep Trueta, Girona, Spain.

 

Aim: The aim of this study is to know the clinical and molecular characteristics of LLS and to analyze if there are clinical, pathology or molecular characteristics that could suggest a hereditary or sporadic origin.

Method: This is a multicenter nation-wide study (25 Spanish hospitals).  Patients were included when CRC tumors showed immunochemical loss of MSH2, MSH6, PMS2 or loss of MLH1 with BRAF-WT and/or no MLH1 methylation and absence of pathogenic mutation in these genes.

Results: Our study included 160 LLS patients. Loss of MLH1/PMS2 was found in 48% of CRC, loss of MSH2/MSH6 in 25%, loss of MSH6/PMS2 in 2%, isolated loss of MSH6, PMS2 and MSH2 was found in 11%, 9% and 2% respectively. In 3% of patients no gene loss of expression was found. 5 patients (3%) developed CRC during the follow up time since diagnosis, (median time of 7 years (SD 3.95)); 20 patients (12.5%) had personal history of non-CRC, and only 5 (3%) patients had LS-related cancer history.

Conclusion: In this LLS cohort, the largest until now, there are no clinical, molecular or pathological characteristics that could help distinguish between probably sporadic and hereditary patients. These results support the need of homogeneous follow-up for this group of patients.

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