Quantitative analysis of marker expression in epicardial cells differentiated from hPSCs via small molecule modulation of Wnt signaling (Step 15C). Epicardial cells (Epi) were generated from H13 hESCs as described in Fig. 2. At day 48, 10–50 k cells were analyzed for cTnT/WT1 expression by flow cytometry with percentages of cTnT: 0.3±0.1 and WT1: 96.3±0.8, compared to cTnT: 94.6 ± 1.5 and WT1: 0.2 ± 0.1 of cardiomyocytes (CMs). Data are presented as mean ± S.D. from three independent experiments: epicardial cell WT1 (95.6%, 96.1%, 97.2%) and cTnT (0.3%, 0.2%, 0.4%) and cardiomyocyte WT1 (0.4%, 0.1%, 0.2%) and cTnT (94.7%, 96%, 93%).