TGFB1 and neoplasm: Of note, the fact that p19Arf level did not strictly inversely correlate with C/ebpβ (Figure 1D, lane 3 versus 1) indicates that other factors, such as cell “culture shock” that has been described for cultured mouse fibroblasts [27], must play a role in expression of this tumor suppressor and these other factors maybe be independent of Tgfβ signaling (see more below).