Exhibit 99.1 Castle Biosciences Reports First Quarter 2026 Results Delivered Q1 2026 revenue of $83.7 million Q1 2026 total test reports for our core revenue drivers (DecisionDx -Melanoma, TissueCypher ) increased 36% over Q1 2025 Raising full-year 2026 revenue guidance to $345-355 million from $340-350 million Conference call and webcast today at 4:30 p.m. ET ® ® FRIENDSWOOD, Texas – May 6, 2026 – Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patien ...