BCOR and myasthenia gravis: In our cases of thymomas from patients with myasthenia gravis, we identified a trend for the presence of mutually exclusive mutations of GTF2I and BCOR. BCOR is a tumor suppressor gene that encodes for an epigenetic regulator involved in the specification of cell differentiation and body structure development and takes part in the non-canonical polycomb repressive complex 1 (47).