Figure 4

CD44⁺CD54⁺ cells derived from rectospheres have the strongest tumorigenicity among the four cellular subpopulations. (a) Tumor-bearing mice derived from 100, 500, 1000, and 10 000 CD44⁺CD54⁺ rectal cancer cells and excised subcutaneous tumors. One representative experiment of three different tumors is shown. (b) Size of xenografts of CD44⁺CD54⁺ and CD44⁺CD54⁻ derived from rectospheres. Data are mean tumor size±S.D. of 3–5 tumors per group derived from three separate patients (patients 9, 11, and 15). (c) Hematoxylin and eosin analysis of a human rectal cancer section from the original human tumor and corresponding xenografts obtained after injection of sphere cells. Bars=100 μM. Second and third xenografts: tumors were obtained from the first and second transplantation, respectively. One representative experiment of two different tumors is shown. (d) Immunohistochemical analysis of relative differentiation and putative R-CIC markers in tissue derived from original human tumor (left panel) and sphere-derived first xenografts (right panel). One representative experiment of two different tumors is shown. Bars=100 μM. (e) Size of xenografts of CD44⁺CD54⁺ and CD44⁺CD54⁻ sorted from three rectal cancer tissues. Data are mean tumor size±S.D. of 3–5 tumors per group derived from three separate patients (**P<0.01, *P<0.05; patients 31, 32, and 33)