Utilization of Whole Exome Sequencing to Identify Hereditary Mutations in Palestinian Families with Hereditary Cancers

Cancer control efforts in Palestine have largely centered on treatment, with limited focus on understanding the genetic landscape of cancer in the Palestinian population. Advances in high-throughput genetic and genomic technologies provide powerful tools to uncover cancer-associated mutations and inform targeted therapies, yet these approaches remain underutilized in Palestine. Our project addresses this gap by integrating genetic and functional techniques to identify hereditary cancer mutations, assess their pathogenic potential, and explore their role in tumorigenesis. We recruited families with a history of hereditary cancer and conducted BRCA panel sequencing on probands using Illumina iSeq. Whole Exome Sequencing was then performed on all BRCA wild type patients. Briefly, DNA libraries were prepared using the Illumina DNA Prep with Enrichment kit and sequenced on the NextSeq550 platform at 40X depth. Variant annotation was performed with SnpEff, and filtered variants were further assessed using in silico prediction tools. Candidate mutations were validated via Sanger sequencing, and segregation analyses were performed within affected families. In Family I, a splice site variant in RAD50 (c.2524+3A>G) segregated in an autosomal dominant manner and was shown by cDNA analysis to cause exon skipping, predicting disruption of the MRN DNA repair complex. Family II harbored a truncating MSH4 nonsense variant (c.328C>T, p.R110X), consistent with loss of protein function, as well as a missense STAT6 variant (c.1216C>G, p.L406V) that segregated dominantly among affected individuals and is predicted to alter DNA binding dynamics. In Family III, a splice region variant in PRKAR1A (c.973+6T>C) was identified, suggesting impaired splicing and loss of tumor suppressor activity. Collectively, these findings expand the spectrum of hereditary cancer-associated variants in an underrepresented population and demonstrate the utility of whole exome sequencing for uncovering clinically relevant mutations in Palestinian families.