KRT7 and carcinoma: Immunohistochemistry has been performed and revealed that the carcinoma was strongly and diffusely positive for cytokeratin 7 (CK7), GATA-binding protein 3 (GATA3), and p40 (Figures 7-8), and was negative for oestrogen receptor (ER), progesterone receptor (PR), and paired box gene 8 (PAX8) (Figures 9-10).