SPEN and cancer: Singleton mutations were found in 3 of the 263 genes recurrently mutated across cancer as annotated by the ‘PanCan’ dataset [35, 36]: BAP1 (p.T517M in S23 from P13), ARHGAP35 (p.E1273A in S17 from P13), and SPEN (p.A1813T in S7 from P6) (Table 1).