All cancers used in this study were selected on the basis of molecular features (negative for estrogen receptor, progesterone receptor, and HER2 expression, and positive for CK5/6 or EGFR expression) and also on the morphology represented in these three panels, with highly atypical cells, pushing borders, and minimal ductal differentiation. Note the areas of necrosis in the case shown on the left. The three cases shown in this figure are the same as those shown in figure 5 below.