Serum Visfatin/NAMPT as a Potential Risk Predictor for Malignancy of Adrenal Tumors

Abstract

Adrenocortical carcinomas (ACC) are rare endocrine malignancies, often with a poor prognosis. Visfatin/NAMPT regulates a variety of signaling pathway components, and its overexpression has been found in carcinogenesis. Our study aimed to assess the clinical usefulness of visfatin/NAMPT serum level in discriminating between ACC and benign adrenocortical tumors. Twenty-two patients with ACC and twenty-six patients with benign adrenocortical tumors were recruited. Fasting blood samples were collected from each patient, and visfatin serum levels were measured with the ELISA Kit. Clinical stage, tumor size, Ki67 proliferation index, hormonal secretion pattern, and follow-up were determined in ACC patients. Patients with ACC had significantly higher visfatin serum concentrations (7.81 ± 2.25 vs. 6.08 ± 1.32 ng/mL, p-value = 0.003). The most advanced clinical stage with metastases was associated with significantly elevated visfatin levels (p-value = 0.022). Based on ROC analysis, visfatin serum concentrations higher than 8.05 ng/mL could discriminate ACC with a sensitivity of 50.0% and specificity of 92.3%. Univariate Cox regression indicated that tumor size was significantly related to shorter survival, and the visfatin level was borderline significant in all patients (HR = 1.013, p-value = 0.002, HR = 1.321, p-value = 0.058). In the Kaplan-Meier method, patients with visfatin serum concentrations higher than 6.3 ng/mL presented significantly lower survival probability (p-value = 0.006). Serum visfatin/NAMPT could be a potential risk predictor for the malignancy of adrenal tumors. However, further studies are needed on this subject.

Keywords: NAMPT; adrenocortical carcinoma; benign adrenocortical tumor; nicotinamide phosphoribosyltransferase; visfatin.

Figure 1

Comparison of visfatin serum concentrations between patients with adrenocortical carcinomas and benign adrenocortical tumors (p-value for Welch’s t-test).

Figure 2

Receiver operating characteristic curve determining the potential of serum visfatin to discriminate between adrenocortical carcinomas and benign adrenocortical tumors (with presented proposed cut-off based on the Youden’s index).

Figure 3

Kaplan-Meier curves presenting the survival probability for patients with all adrenocortical tumors depending on visfatin serum level for 10 years of follow-up.