**3.** Mucin-1 (Muc-1)

Muc-1 is a glycoprotein expressed by endometrium and fallopian tube epithelium involved in implantation [96]. Muc-1 expression was observed to be lower in luminal epithelial of tubes with ectopic pregnancies [97]. Similar findings were observed by Reefaat et al [98]. However, the role of serum Muc-1 as a diagnostic modality has not been studied in much detail.
