Twist performed a literature search to arrive at a list of curated, clinically-relevant (i.e. actionable) cancer-associated variants, as well as using the COSMIC database as a reference, where matching entries are available It includes the many prevalent variants in adult solid tumors. The 456 variants occur in 85 unique genes. Twist also separately annotates   the set of clinical relevant variants (>140 of variants).

The configuration of variants and their precise reference and alternative sequence are listed on the Twist website.