Assessing the diagnostic yield of targeted next-generation sequencing for melanoma and gastrointestinal tumors

In this study, we compared clinical diagnostic yield of TruSight Tumor 26 Sequencing Panel (TST26) in melanoma, colorectal (CRC) and gastro-intestinal stromal (GIST) tumors to non-NGS assays. 1041 formalin-fixed, paraffin embedded (FFPE) tumors, of melanoma, CRC and GIST were profiled. NGS results were compared to non-NGS single-gene or single-variant assays with respect to variant output and diagnostic yield. 79% melanoma and 94% CRC tumors were variant-positive by panel testing. TST26 panel improved BRAF variant detection in melanoma as compared to single-variant BRAF V600E/K routine tests by 24% and also detected variants in genes other than BRAF, NRAS and KIT which could impact patient management in 20% additional cases. NGS enhanced diagnostic yield in CRC by 36% when compared to routine single gene assays. In contrast, no added benefit of NGS based testing for GIST tumors was observed.TST26 panel either missed or inaccurately called complex insertion/deletion variants in KIT exon 11, which were accurately identified by non-NGS methods. Our findings demonstrate the differential impact of cancer site and variant type on diagnostic test information yield from NGS assays.
Source: The Journal of Molecular Diagnostics - Category: Pathology Source Type: research