Figure 4.

Subcutaneous injection of transformed murine MSCs result in tumor formation with variable histology. (A) H&E staining of tumors formed after subcutaneous injection of transformed murine MSCs (B6_4, B6_7, B6_10). Tumor B6_4 displayed a moderately cellular and pleomorphic tumor with deposition of amorphous eosinophilic extracellular matrix, suggestive of osteoid (indicated with asterisks). In contrast, tumors B6_7 and B6_10 were more cellular, pleomorphic, with a high number of mitoses, and morphologically lack any differentiation. Atypical mitosis were present, indicated with an arrow in B6_10. Tumor volumes for B6_4, B6_7 and B6_10 were 0.005 cm³ (n = 2), 0.4–1.1 cm³ (n = 3) and 0.3–0.6 cm³ (n = 3), respectively. Scalebar represents 50 µm. (B) Number of days after subcutaneous injection when mice were sacrificed due to an increase in tumor volume. (C) Tumor size measured by calliper of each mouse after subcutaneous injection of transformed murine MSCs (t = 0).