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 48303 1394507.61 28007301 12/13/2024 NASD Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 3030 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 2844 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 900 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 897 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 897 10/29/2007 None Common 10/29/2007 Acquired as gift Derek Maetzold Y 10/29/2007 897 10/29/2007 None Common 12/10/2020 Acquired as compensation -- Restricted Stock Units Issuer N 3252 12/10/2020 Compensation Common 12/10/2021 Acquired as compensation -- Restricted Stock Units Issuer N 9355 12/10/2021 Compensation Common 12/09/2022 Acquired as compensation -- Restricted Stock Units Issuer N 20315 12/09/2022 Compensation Common 05/12/2020 Acquired upon option exercise Issuer N 4930 05/12/2020 Option exercise Common 12/23/2022 Acquired as compensation -- Performance Awards Issuer N 986 12/23/2022 Compensation N The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/09/2024 512 15081.83 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/09/2024 150 4418.51 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/09/2024 150 4418.51 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/09/2024 996 29338.87 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/09/2024 478 14080.3 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/09/2024 150 4418.51 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/09/2024 150 4418.51 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/08/2024 505 15285.95 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/08/2024 149 4510.11 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/08/2024 149 4510.11 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/08/2024 986 29845.43 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/08/2024 474 14347.6 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/08/2024 149 4510.11 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/08/2024 150 4540.38 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/11/2024 512 15523.74 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/11/2024 160 4851.17 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/11/2024 160 4851.17 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/11/2024 996 30198.52 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/11/2024 478 14492.86 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/11/2024 160 4851.17 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/11/2024 150 4547.97 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 505 16411.24 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 149 4842.13 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 149 4842.13 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 986 32042.54 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 474 15403.82 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 149 4842.13 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 150 4874.63 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/04/2024 505 14510.77 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/04/2024 150 4310.13 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/04/2024 150 4310.13 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/04/2024 986 28331.92 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/04/2024 474 13620.01 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/04/2024 150 4310.13 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/04/2024 150 4310.13 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 505 15780.64 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 149 4656.07 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 149 4656.07 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 986 30811.32 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 474 14811.93 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 149 4656.07 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 150 4687.32 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 505 16184.39 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 150 4807.24 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 150 4807.24 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 986 31599.62 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 474 15190.89 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 150 4807.24 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 10/14/2024 150 4807.24 The Maetzold Descendants 2020 Trust dtd 12/4/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 505 15501.03 The Maetzold 2018 Remainder Trust f/b/o John Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 150 4604.27 The Maetzold 2018 Remainder Trust f/b/o Peter Douglas Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 150 4604.27 Derek Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 986 30265.37 Derek Maetzold 2020 Irrevocable Trust dtd 12/04/2020 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 474 14549.48 The Maetzold 2018 Remainder Trust f/b/o Hannah Elizabeth Maetzold 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 150 4604.27 The Maetzold 2018 Remainder Trust f/b/o Emily Carol Kirk 505 S. Friendswood Drive Suite 401 Friendswood TX 77546 Common 09/16/2024 150 4604.27 Total number of shares to be sold includes: 38,838 shares by Derek Maetzold, 2,844 shares by DM 2020 Irrev Tr, 3,030 shares by Maetzold Descendants 2020 Tr, 897 shares by Hannah Maetzold Irrev. Trust, 897 shares by Peter Maetzold Irrev. Trust, 900 shares by Emily Maetzold Irrev. Trust, 897 shares by John Maetzold Irrev. Trust. The sales of shares set forth herein are made in connection with a selling plan dated 5/24/2024 that is intended to comply with Rule 10b5-1(c). 12/13/2024 05/24/2024 Goldman Sachs & Co. LLC on behalf of Derek Maetzold