Upon presentation, his circulating tumor DNA (ctDNA) was sequenced using the Guardant 360 assay and notably showed microsatellite instability (MSI-high) and MSH6 S702* loss; BRCA2 copy number loss/loss of heterozygosity along with 2 BRCA2 synonymous mutations (V1438V and V821V); several AR mutations: W742C, W742L, M896V, P893S, and S889G; SMAD4 mutations: R361H, L540P, and RB1 R661W; and significantly elevated TMB 109 mut/Mb. The gene discussed is MSH6; the disease is neoplasm.