2029P - Exploring the role of genes associated with familial cancer syndromes on the development of multiple primary tumors

Abstract

BackgroundOver the past decade an increase in the incidence and severity of multiple primary neoplasias has been observed. The main causes of multiple primary tumors (MPT) are genetic factors, environmental factors, infections with oncogenic viruses, etc. The aim of the current study was to explore the role of genes associated with familial cancers in MPT development. MethodsThe study included 12 MPT patients, of which 6 women with metahronous/synchronous breast and ovarian tumors; and 6 men who developed primary tumors with different localisation: bladder/bile ducts; rectum/pancreas; prostate/colon; prostate/sigma; sigma/stomach; palate/larynx+hypopharynx/tongue, respectively. Seventy five (9/12) of the patients had family history of cancer and 50% (6/12) early onset (<50y). Mutational screening was performed by NGS of a panel of 94 tumor-associated genes on MiSeq platform (Illumina). ResultsA total of 82 variants were found of which 18.3% were evaluated as clinically significant. Among selected variants 33.3% (5/15) were pathogenic, 13.3% (2/15) likely pathogenic and 53.3% (8/15) variants of uncertain significance (VUSs). Pathogenic/likely pathogenic variants were detected in the genes BRCA1 (20%), MLH1 (13.3%), BRCA2 (6.7%) and CDH1 (6.7%) while VUSs in PMS1, GPC3, DIS3L2, PRF1, STK11, DICER1, RET, and MSH6, respectively. ConclusionsOverall, the genetic cause of MPT was found in 58.3% (7/12) of the patients. Further research is needed to evaluate the functional effect of all VUSs. Legal entity responsible for the studyMedical University of Sofia. FundingMedical University Sofia; National Science Fund, Ministry of Education and Science, Bulgaria. Grants D-71/03.05.2018/MU-Sofia; KP-06-OPR03/1719.12.2018/NSF; DUNK01-2/2009/NSF, MES Bulgaria. DisclosureAll authors have declared no conflicts of interest.