MUC1 (VPM654 and EPR1023) Expression in Mucosa of Fallopian Tubes With Ectopic Pregnancy is Altered.

MUC1 is a surface glycoprotein that has an external and an internal domain. A recent report has shown that 1 segment of the external domain is reduced in ectopic pregnancy, suggesting that MUC1 may provide a protective mechanism against ectopic pregnancy. The objective of this study was to analyze the protein expression of 4 antibodies against MUC1 in fallopian tubes with or without ectopic pregnancy. Tissue sections of ectopic pregnancies (n=10) and normal tubes (n=16) derived from surgery were analyzed for the intensity of the staining with 3,3'-diaminobenzidine (DAB). Paraffin sections were submitted to immunohistochemical analysis using 4 different antibodies against different epitopes for MUC1: 214D4, EPR1023, HMFG1, and VPM654. Intensity of the immunostaining (DAB) was measured with ImageJ software. Statistical analysis was performed using Student unpaired t test, Mann-Whitney U test, and ANCOVA. The mean intensity of MUC1 [mean±SD, or median (interquartile)] in the mucosa of fallopian tubes with ectopic pregnancy was higher for EPR1023 (23.73±13.63 vs. 8.5±5.1, P=0.006), and reduced for VPM654 [13.7 (13-16.2) vs. 22.5 (19.5-29.7), P=0.005] compared with normal tubes. No difference was found for 214D4 and HMFG1. The immunoexpression of different epitopes (external and cytoplasmic) of MUC1 expression are altered in tubes with ectopic pregnancy compared with normal tubes, suggesting an association to explain its etiology.