Suppression of in ovo teratoma formation of iPSCs by BV treatment. (A,B) On ED day 10, Matrigel plugs containing BV-treated or -untreated iPSCs were loaded on CAMs and then further grown for 8 days in an egg incubator. On ED day 18, teratomas were excised from chorioallantoic membrane (CAM), photographed, and measured for weight. Data are expressed as means ± SD (n = 5). **p < 0.01 vs. BV-untreated control (C) Teratomas generated from BV-untreated iPSCs were analyzed after hematoxylin-eosin (H&E) staining. Arrows indicate cells derived from three germ layers, including ectoderm, mesoderm, and endoderm, respectively.