Optimized Immunohistochemistry for SMARCA2

All assays were performed on formalin-fixed paraffin-embedded slides. Immunohistochemistry staining for SMARCA4 was performed as previously described.^{2 (link)} The immunohistochemistry method for SMARCA2 was optimized as follows: heat steaming with EDTA at pH 8 for 30 min resulted in epitope retrieval. Antigen retrieval followed by overnight incubation at 4 ^oC with primary antibody targeting SMARCA2 (Sigma-Aldrich, St. Louis, MO, USA; #HPA029981, dilution 1:1000). Biotinylated anti-Rabbit IgG (Vector Laboratories, Burlingame, CA, USA; #BA-100, dilution 1:1000) and ABC (Vector Laboratories; #PK-6100) were used to detect the bound antibody. Diaminobenzidine was used as the chromogen. Absence of nuclear staining in tumor cells in the presence of internal positive control (blood vessels and stromal cells) was scored as ‘loss of expression'.