RB1 and endometriosis: Since the levels of both isoforms of PR in human endometrium have been found to be abnormal in patients with endometriosis[33, 34], we evaluated the immunoreactive presence of PR-A/B (Figures 3A and3C), PR-B (Figures 3D and3F) along with Sp1 (Figure 3G and3I) and the P-regulated glycoprotein glycodelin (Figures 3 J and3L) in paraformaldehyde-fixed paraffin embedded endometrial tissue from groups A, B and C by IHC.