ATF6 and adenoma: As atypia became more severe, the level of ATF6 expression increased; the median ATF6-IHC score was 2.0 (range, 0–4) in adenoma with moderate atypia, 5.0 (range, 0–8) in adenoma with severe atypia, and 7.0 (range, 3–14) in pTis cancer.