CCND1 and neoplasm: As far as cyclin D1 is concerned, all cases of EWS (14/14) displayed a strong and diffuse nuclear expression (>50% positive cells) (Figure 2), including two cases in which the immunostaining for CD99 was not only heterogeneous but also focally extended into tumor stroma (non-specific immunostaining) due to sampling artefacts (Figure 5).