Supplementary Figure 1.Optimization IHC on pilot series of cHL cases. from Classical Hodgkin Lymphoma with Reduced β<sub>2</sub>M/MHC Class I Expression Is Associated with Inferior Outcome Independent of 9p24.1 Status

<p>Three distinct patterns of staining of HRS cell membranes were observed relative to the staining of reactive inflammatory cells: "positive" (Pos), "decreased" (Dec) and "negative" (Neg) for β2M, MHC class I and MHC class II. CHL #1: β2M and MHC class I positive, MHC class II negative; cHL #2: beta2M and MHC class I decreased, MHC class II positive; cHL #3: beta2M and MHC class I negative, MHC class II decreased. Black arrows highlight individual HRS cells or two adjacent HRS cells with distinct patterns of membrane staining, as indicated.</p>