biofluids embryo implantation endometrial fluid hplc-ms/ms mucins proteomics adult article clinical trial disease marker electrophoresis endometriosis endometrium endometrium cancer female human human cell menstrual cycle nidation normal human polyacrylamide gel electrophoresis priority journal protein analysis protein database protein determination protein isolation proteomics reversed phase high performance liquid chromatography tandem mass spectrometry two dimensional gel electrophoresis uterus fluid adolescent adult amino acid sequence biopsy; needle body fluids chromatography; high pressure liquid cluster analysis electrophoresis; gel; two-dimensional embryo implantation endometrial neoplasms endometriosis endometrium female humans isoelectric focusing luteal phase middle aged molecular sequence data mucins peptides proteome proteomics tandem mass spectrometry