Trophoblast glycoprotein (TPGB/5T4) in human placenta: expression, regulation, and presence in extracellular microvesicles and exosomes by Alam, SMK, Jasti, S, Kshirsagar, SK, Tannetta, DS, Dragovic, RA, Redman, CW, Sargent, IL, Hodes, HC, Nauser, TL, Fortes, T, Filler, AM, Behan, K, Martin, DR, Fields, TA, Petroff, BK, Petroff, MG