HLA-E and metastatic neoplasm: As shown in Figure 2, plasma levels of sHLA-E were higher in patients with localized than in those with metastatic disease ((a) arbitrary units/mL ± SD; localized: 0.26 ± 0.07, metastatic 0.18 ± 0.08, P = 0.0002), whereas plasma levels of sHLA-F ((b) arbitrary units/mL ± SD; localized: 0.88 ± 0.2, metastatic 0.71 ± 0.37) were similar in the two subsets.