Clustering of trophonin, a cell adhesion molecule in human endometrial adenocarcinoma SNG-M cells. (Inset) Tangential (X-Z) section through SNG-M cells stained with anti-trophonin antibodies. Trophonin has been implicated in embryo adhesion to the wall of the uterus during human implantation. Dr. Michiko Fukuda, the Burnham Institute.