Immunohistochemically, TKTL1 expression was found in all tissue types, normal mammary glands (n = 5/6, 83%; IRS = 1, range 0–12), hyperplastic lesions (n = 3/3, 100%; IRS = 12, range 9–12), complex adenomas (n = 5/5, 100%; IRS = 1, range 0–6), simple adenomas (n = 6/6, 100%; IRS = 8, range 1–12), complex carcinomas (n = 5/6, 83%; IRS = 1, range 0–12) and simple carcinomas (n = 11/11, 100%; IRS = 3, range 1–12) (Fig. 4) (Additional file 1). Here, TKTL1 is linked to adenoma.