Table 2. Clinical Expert Perspectives: Categories of Sequencing Targets Included in Next-Generation Tumor Sequencing Panels and Corresponding Uses.

Target Categorya	Description	How It May Be Used	Type of Use
Established targets	Standard-of-care alterations: proven validity and utility for specific cancers acknowledged by guidelines and/or covered by payers	Guide the use of a targeted therapy approved for specific cancer (predictive targets)	Clinical
		Inform prognostication (prognostic targets)	Clinical
		Match a patient to a biomarker-driven clinical trial of a novel drug for an established target	Research
Novel targets	Alterations with known or suspected, but less proven validity and/or utility, or new alterations for known tumor suppressor genes with existing targeted therapies	Guide the use of targeted therapy if available for established variant of same gene	Clinical or research
		Match patients to biomarker-driven clinical trials, if available	Research
		Inform genomic and drug discovery	Research
Pan-cancer targets	Alterations with established validity and utility in another cancer	Guide the use of an approved targeted therapy based on the target/drug model from another cancer	Clinical or research
All of the above	Enhanced understanding of a patient's tumor	Assess tumor heterogeneity	Clinical or research
		Determine tumor pathways (eg, resistance to therapies)	Clinical or research
		Assess temporal tumor behavior and evolution during treatment (via repeat monitoring)	Clinical or research

^aTumor genetic or molecular alterations and biomarkers interrogated by next-generation sequencing panels.