Immunohistochemical staining for Ki67, TGF-β1 and apoptosis by TUNEL in explants of human endometrium throughout the menstrual cycle obtained from normal (A, C, E, G, I, J and K) and endometriosis (B, D, F, H and L) women. Representative human endometrium explants from (A, B, E, F and I) proliferative phase and (C, D, G, H, J, K and L) secretory phase of the menstrual cycle with positive immuno-staining for (A-D) Ki67 and (E-H) TGF-β1 or positive DNA fragmentation by TUNEL (K and L). Immunohistochemitry (I) and TUNEL (J) negative controls. Cell nuclei are stained with haematoxylin (immunohistochemitry) or propidium iodine (TUNEL). g: glandular, s: stroma, rc: red blood cell. Magnification, 400×.