Figure 2.

Ki67 assessment: panels a) and b) depict two matching fields from case 18, with major discrepancy in Ki67 count among different labs (respectively, 59.5% from lab F vs 19% from lab G), reasonably impacted by a diversity in staining intensity and interpretation of weaker signals (centralized manual count was, respectively, 46.5% and 31.5%).

p53 assessment: panels c) and d) exemplify the pattern of positivity among two «p53 high» cases from lab F, respectively, case 10 (TP53 mutated) and case 20 (TP53 mutated plus 17p deleted); intensity is variable but consistent, or «clonal», as compared e) with the variable intensity in case 8 (TP53 wild type, del17p negative), scored intermediate at lab C.

SOX11 assessment: though heterogeneous (f, g; respectively, case 9 and 1, lab C), the consistency of SOX11 staining among each given case allows an easy assessment of SOX11 positivity, as compared to «low positive» (h, case 18, lab C) and true negative cases, which at times harbour only isolated positive cells in an homogeneously negative background.