X0202 SCHEDULE 13G/A 0001104659-25-034639 0001350290 XXXXXXXX LIVE 1 Common Stock, $0.001 par value per share 03/31/2026 0001447362 Castle Biosciences, Inc. 14843C105 1500 W. Parkwood Ave. Suite 400 Friendswood TX 77546 Rule 13d-1(c) Portolan Capital Management, LLC DE 1350283.00 0.00 1350283.00 0.00 1350283.00 N 4.45 IA George McCabe X1 1350283.00 0.00 1350283.00 0.00 1350283.00 N 4.45 IN Castle Biosciences, Inc. 1500 W. Parkwood Ave, Suite 400, Friendswood, TX 77546 This statement is being filed with respect to the shares Common Stock of the Issuer beneficially owned (1) directly by Portolan Capital Management, LLC, a registered investment adviser, in its capacity as investment manager for various clients, and (2) indirectly by George McCabe, the Manager of Portolan Capital Management, LLC. Portolan Capital Management, LLC and Mr. McCabe are sometimes individually referred to herein as a "Reporting Person" and collectively as the "Reporting Persons." The address of the principal business office of each of the Reporting Persons is 2 International Place, FL 26, Boston, MA 02110 Portolan Capital Management, LLC - DE Mr. McCabe - USA Y The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated by reference herein. The information required by Item 4(b) is set forth in Row 11 of the cover page for each of the Reporting Persons and is incorporated by reference herein. The information required by Item 4(c) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated by reference herein. 0 The information required by Item 4(c) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated by reference herein. 0 N Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Portolan Capital Management, LLC George McCabe 05/15/2026 George McCabe George McCabe 05/15/2026