Table 2: Correlations between serum biomarkers and clinical parameters.

Sex N-myc
amplification
Age at diagnosisStage
FMNo Yes <18 m>18 m1–3 4

Chromogranin
 Below 6.16 pg/mL1839401830283324
 Above 6.16 pg/mL17a101791115918
HLA-E
 Below 0.216 AU/mL2023311017301235
 Above 0.216 AU/mL1526331024a1335a2
HLA-F
 Below 0.995 AU/mL1434401420311833
 Above 0.995 AU/mL1422181221a1229a4
 Below 0.445 AU/mL1014176717222
 Above 0.445 AU/mL2238412034a2645a15

P < 0.05 (Fisher’s exact test).