METHODS: Plasma
IGFBP-2 was determined in 51 patients referred to our institutions for adrenocortical
tumors. Fifteen patients were
in complete remission (group 1), eight patients had preoperative localized
tumors (group 2) and 28 patients had metastatic
tumors (group 3). Thirty-six healthy volunteers constituted a control group.
RESULTS: There was no significant difference in plasma
IGFBP-2 concentration between healthy controls and patients with complete remission or localized
tumors. In contrast, patients with metastatic disease had significantly higher
IGFBP-2 plasma levels than the control group (P<0.001).
IGFBP-2 levels in patients with metastatic disease were inversely correlated with survival (R2=0.308; P=0.0026). In patients with localized
tumors, there was no correlation between plasma
IGFBP-2 concentration and
tumor size or histological features. Analysis of individual
IGFBP-2 concentrations showed that five patients (17.8%) with metastatic
tumors had normal
IGFBP-2 levels and two patients (13.3%)
in complete remission had high plasma
IGFBP-2 levels. The influence of nutrition,
hormone secretion and treatment on
IGFBP-2 levels was examined. Nutritional status was evaluated by determining
IGF-I levels and was found to be normal in 16 patients (61.5%) with high
IGFBP-2 levels, suggesting that
malnutrition was not responsible for the high
IGFBP-2 concentrations in these patients.
IGFBP-2 levels did not differ significantly according to
tumor secretion or
mitotane treatment. In a follow-up study, plasma
IGFBP-2 concentration remained stable in patients with complete remission or stabilized disease and was a late marker of
tumor progression in patients with progressive metastatic disease.
CONCLUSIONS: These results indicate that plasma
IGFBP-2 is elevated in patients with malignant adrenocortical
tumors and that the major factor affecting
IGFBP-2 levels in these patients is
tumor stage. However, plasma
IGFBP-2 was less sensitive than expected for a
tumor marker, which may limit its value in the diagnosis and follow-up of
adrenocortical carcinoma.