The expression of stem cell markers in hACL-SCs and hMCL-SCs. Both types of ligament stem cells expressed nucleostemin (A, B, C), SSEA-4 (D, E, F), CD44 (G, H, I), and CD90 (J, K, L), but not CD31, CD34, CD45, and CD146 (not shown). Note that negative controls (omission of primary antibodies) were also used in the immunostaining, and no staining signals were seen (data not shown). Also, the results shown here were obtained from a of 26-year-old male donor (see Table 1). The passage 1 cells were used in immunostaining. (Bar: 100 μm).