X0508 4/A 2025-08-27 2025-08-29 0 0001447362 CASTLE BIOSCIENCES INC CSTL 0001856565 Oelschlager Kristen M C/O CASTLE BIOSCIENCES, INC. 505 S FRIENDSWOOD DRIVE, SUITE 401 FRIENDSWOOD TX 77546 0 1 0 0 Chief Operating Officer 0 Common Stock 2025-08-27 4 S 0 18007 21.69 D 100937 I The Fritz Shorter Trust Common Stock 52924 D This transaction was executed in multiple trades at prices ranging from $21.24 to $21.94, inclusive. The price reported above reflects the weighted-average sale price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. On August 29, 2025, the Reporting Person filed a Form 4 which inadvertently reported that shares were sold by the Reporting Person directly. In fact, as reported in this amendment, the shares were sold by the Fritz Shorter Trust (the "Trust"). The original Form 4 also mistakenly indicated the wrong number of shares held by the Reporting Person directly and indirectly through the Trust. In fact, following this sale, the Reporting Person held 52,924 shares of common stock directly and 100,937 shares of common stock indirectly through the Trust. In addition, following a reconciliation of the reporting person's holdings, it was determined that the balance previously reported was understated by 68 shares, and the holdings reported herein have been adjusted accordingly. On March 19, 2025 and on August 22, 2025, the Reporting Person transferred 96,322 and 22,622 shares to the Trust. The transfer was not a change in beneficial ownership because the Reporting Person and her spouse are the trustees and sole beneficiaries of the Trust, the Trust is revocable and the Reporting Person has voting and investment power over the shares held by the Trust. /s/ Frank Stokes, Attorney-in-fact 2025-11-04