Appendix 3. WT1 IHC Assessment and Documentation Form SELLAS Life Sciences Group Galinpepimut -S Protocol : SLS17 -201/ MK3475 -770 Protocol v1.1 (Amendment 1.0) 12 April 2019 Page 259 CLINICAL STUDY PROTOCOL SLS17-201/ MK3475-770 A PHASE 1/2 STUDY OF GALINPEPIMUT-S IN COMBINATION WITH PEMBROLIZUMAB (MK-3475) IN PATIENTS WITH SELECTED ADVANCED CANCERS WT1 IHC Assessment and Documentation Form Assessment of Tumor Positivity for Expression of WT1 in Biopsy Material by WT1 Immunohistochemistry (IHC) Per Section 4.1.1. (Subject Inclusion Criteria), subheading 4 (b). of of the protocol: Patients’ metastatic disease deposits (for patients with solid tumors)/bone marrow leukemic cell deposits (for patients with AML) will be evaluated for WT1 protein expression, as detectable by IHC analysis of banked (paraffin -embedded) or freshly biopsied tumor material. • IHC evidence of WT1 expression will be performed according to the technique described by Dupont et al. (Gynecol Oncol.