Homologous recombination deficiency (HRD) is a cellular weakness resulting from the disruption of a major DNA repair pathway. HRD status can be identified by tumor testing. Because the homologous recombination (HR) pathway can be disrupted by many mechanisms beyond just genetic mutations, relying solely on gene sequencing may miss tumors with other causes of HRD, both known (such as promoter methylation) and unknown.
Relying solely on gene sequencing may miss tumors with other causes of HRD
Myriad’s newest companion diagnostic, myChoiceTM HRD, is an algorithmic measurement of three biomarkers associated with homologous recombination deficiency, combined with next-generation sequencing of the BRCA1 and BRCA2 genes in the tumor. The three biomarkers, loss of heterozygosity (LOH), telomeric allelic imbalance (TAI), and large-scale state transitions (LST), have all been individually shown to be associated with BRCA1/2 deficiency.1
