Whilst a subdivision of membrane staining was difficult to measure due to small sample sizes in membrane-expressing tissues, the highest expression in the benign group for the total SFRP4 expression was in the tubal epithelium, followed by endometriosis and lowest in ovarian surface epithelium and inclusion cysts (Figure 3.1 B; Tube vs. OSE, p<0.0001; Tube vs. Endometriosis, p = 0.014). Here, SFRP4 is linked to endometriosis.