SMN1 and neoplasm: Tumour cells were positive for S-100 (100%, 41/41, 36 for diffuse positive and 5 for focal positive), diffuse SOX10 (100%, 23/23), p63 (100%, 43/43, 33 for diffuse positive and 10 for focal positive) and variable SMA (42%, 10/24) protein, whereas only a few patients were positive for p40 protein.