X0508 4 2025-11-20 0 0001447362 CASTLE BIOSCIENCES INC CSTL 0001856542 Juvenal Tobin W C/O CASTLE BIOSCIENCES, INC. 505 S FRIENDSWOOD DRIVE, SUITE 401 FRIENDSWOOD TX 77546 0 1 0 0 Chief Commercial Officer 1 Common Stock 2025-11-20 4 M 0 4693 3.38 A 89288 D Common Stock 2025-11-20 4 S 0 4693 35.58 D 84595 D Common Stock 2230 I By Tobin W and Susan M Juvenal Family Revocable Trust Stock option (right to buy) 3.38 2025-11-20 4 M 0 4693 0 D 2029-03-12 Common Stock 4693 11210 D This transaction was made pursuant to a Rule 10b5-1 plan adopted by the Reporting Person on September 11, 2024. Reflects an adjustment of 68 shares to the number of shares beneficially owned following a reconciliation of the Reporting Person's records. This transaction was executed in multiple trades at prices ranging from $35.40 to $35.85, 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. Held by Tobin W and Susan M Juvenal Family Revocable Trust of which the Reporting Person and his spouse are the trustees and the Reporting Person, his spouse and their children are the beneficiaries. The shares subject to the option are fully vested. /s/ Frank Stokes, Attorney-in-fact 2025-11-24