IFNA2 and myeloproliferative disorder: Adult male patients aged ≥18 years old diagnosed with Philadelphia-negative MPN (ET, PV, MF, PMF, and prefibrotic PMF) according to the 2008 and/or 2016 WHO criteria and actively receiving treatment including hydroxycarbamide, pegylated interferon 2 alpha (PEG-IFNA2a), and ruxolitinib