SOX2 and neoplasm: Representative microscopic morphological features are shown in Fig. 2A and B. Immunohistochemical staining of paraffin-embedded tissues using a three-step ABC showed that the tumor cells were negative for desmin, S100P, TTF-1, p40, CK7, CK20, SMARCA4 (Fig. 2C), and SMARCA2 (Fig. 2D) and positive for SOX2 (Fig. 2E), CD34, p53, and AE1/AE3 (Fig. 2F).