Assessment of VAV2 Expression Refines Prognostic Prediction in Adrenocortical Carcinoma

Context: Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with overall poor prognosis. The Ki67 labeling index (LI) has a major prognostic role in localized ACC after complete resection, but its estimates may suffer from considerable intra- and interobserver variability. VAV2 overexpression induced by increased Steroidogenic Factor-1 dosage is an essential factor driving ACC tumor cell invasion. Objective: To assess the prognostic role of VAV2 expression in ACC by investigation of a large cohort of patients. Design, Setting, and Participants: A total of 171 ACC cases (157 primary tumors, six local recurrences, eight metastases) from seven European Network for the Study of Adrenal Tumors centers were studied. Outcome Measurements: H-scores were generated to quantify VAV2 expression. VAV2 expression was divided into two categories: low (H-score, <2) and high (H-score, ≥2). The Ki67 LI retrieved from patients' pathology records was also categorized into low (<20%) and high (≥20%). Clinical and immunohistochemical markers were correlated with progression-free survival (PFS) and overall survival (OS). Results: VAV2 expression and Ki67 LI were significantly correlated with each other and with PFS and OS. Heterogeneity of VAV2 expression inside the same tumor was very low. Combined assessment of VAV2 expression and Ki67 LI improved patient stratification to low-risk and high-risk groups. Conclusion: Combined assessment of Ki67 LI and VAV2 expression improves prognostic prediction in ACC.