Table 2 Comparison of different sequencing approaches
Sequencing strategy | Single-gene | Multiplex | Targeted gene | Whole-exome | Whole-genome |
|---|---|---|---|---|---|
| Â | Â | genotyping | sequencing | sequencing | sequencing |
Number of genes | 1 | 20 to 40 | 40 to 100 | >22,000 | >22,000 |
Percentage of genome covered | 0.000075 | 0.005 | 0.03 | 1 | 100 |
Processing time | Rapid (days) | (1–2 weeks) | (>4 weeks) | ||
Cost | Cheap (<$250) | Affordable/economical ($500 to $750) | Expensive (>$5,000) | ||
Mutational profile | Very limited - only for one gene | Will detect mutations in selected genes from pathways relevant to oncogenesis or for which a targeted therapy exists or is in clinical development | Most comprehensive profile | ||
Depth of coverage | Not applicable | >500× for clinical testing, deeper coverage will detect more mutations | Research testing typically 20× to 40×. No guidelines for clinical testing coverage | ||
'Actionable' mutations | Test actionable mutations only | Depends on the design of the panel | Many mutations will not be actionable | ||
Mutations of uncertain clinical significance | No | Few mutations will be of uncertain clinical significance | Many mutations will be of uncertain clinical significance | ||