SFRP4 and ovarian endometrioid adenocarcinoma: Whilst a clear cell and endometrioid ovarian cancer cell line (TOV21D, TOV 112D, respectively) expressed SFRP4 at similar levels to one of the tubal controls, the undifferentiated serous ovarian cancer cell line (SKOV3) displayed very low levels of SFRP4 (Figure 1 A).