Figure 3

Representative case of a non-atypical endometriosis lesion adjacent to clear-cell carcinoma, showing a pattern of heterogeneous immunoreactions for ARID1A. (a) The area of ARID1A-deficient cells is adjacent to the ARID1A-intact area and shows front formation, namely the ‘abrupt loss of ARID1A expression’ (arrow), suggesting that mutations arose in clones within this lesion. (b) Hematoxylin and eosin (HE) staining corresponding to the samples shown in panel a. Regarding the histomorphology or the extent of cellular atypia, the ARID1A-intact and ARID1A-deficient epithelia show similar appearance. Original magnification, × 200 each.