144 0001239501 XXXXXXXX LIVE 0001447362 Castle Biosciences, Inc. 001-38984 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 1-866-788-9007 Derek Maetzold Officer Common Goldman Sachs & Co. LLC 200 West Street New York NY 10282 34821 703732.41 28514109 03/07/2025 NASD Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 4034 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 3462 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 330 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 330 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 330 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 330 10/29/2007 None Common 08/09/2024 Acquired as compensation -- Performance Awards Issuer N 2472 08/09/2024 Compensation Common 03/04/2025 Acquired as compensation -- Restricted Stock Units Issuer N 23533 03/04/2025 Compensation N Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 16 468.14 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 3 87.77 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 2 58.51 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 8 234.07 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 2 58.51 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 2 58.51 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 8 234.07 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 2524 71755.57 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 466 13584.08 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 148 4314.25 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 497 14487.74 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 147 4285.11 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 148 4314.25 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 148 4314.25 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 970 28275.87 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/13/2024 9975 283937.44 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/16/2024 11059 318196.16 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 12/17/2024 9364 264786.88 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 150 4287.56 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 150 4287.56 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 150 4287.56 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 150 4287.56 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 474 13548.67 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 986 28183.53 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 505 14434.76 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 261 7859.66 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 264 7950 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 1729 52066.51 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 261 7859.66 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 831 25024.45 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 886 26680.7 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/06/2025 261 7859.66 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/07/2025 37 1112.89 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/07/2025 124 3729.7 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/07/2025 37 1112.89 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/07/2025 37 1112.89 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/07/2025 36 1082.81 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/07/2025 243 7309.01 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/07/2025 117 3519.15 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/13/2025 505 14124.15 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/13/2025 150 4195.29 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/13/2025 150 4195.29 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/13/2025 150 4195.29 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/13/2025 150 4195.29 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/13/2025 474 13257.13 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 01/13/2025 986 27577.06 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 03/04/2025 2022 42174.27 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 03/04/2025 169 3524.95 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 03/04/2025 169 3524.95 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 03/04/2025 1247 26009.55 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 03/04/2025 1739 36271.54 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 03/04/2025 169 3524.95 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 03/04/2025 172 3587.52 Total number of shares to be sold includes: 26005 shares by Derek Maetzold, 3462 shares by DM 2020 Irrev Tr, 4034 shares by Maetzold Descendants 2020 Tr, 330 shares by Hannah Maetzold Irrev. Trust, 330 shares by Peter Maetzold Irrev. Trust, 330 shares by Emily Maetzold Irrev. Trust, 330 shares by John Maetzold Irrev. Trust. The sales of shares set forth herein are made in connection with a selling plan dated 11/11/2024 that is intended to comply with Rule 10b5-1(c). 03/07/2025 11/11/2024 Goldman Sachs & Co. LLC on behalf of Derek Maetzold