HLA-E and neoplasm: In addition to our previous work [6,26], we provide new evidence for an association of HLA-G and now also HLA-E expression with EwS: Immunohistochemistry analysis of pretherapeutic tumor biopsies detected HLA-E at variable densities in 85% of 26 EwS patients (Figure 4a), compared to 66% of HLA-G positive tumors among 59 EwS patients in a previous report [26].