In the CV group, the serum S100β [median 969.61 pg/mL, interquartile range (IQR) 538.02–2,023.36] and NSE (median 92.18 ng/mL, IQR 63.00–104.12) levels were significantly elevated compared with the PV group (S100β: median 347.30 pg/mL, IQR 242.36–1,029.10; NSE: median 19.81 ng/mL, IQR 17.62–49.08) (p < 0.05). Here, S100B is linked to acquired polycythemia vera.