SMN1 and neoplasm: Factors such as tumor size or vessel maturity (expression of smooth muscle actin, SMA) [9], [40] can affect the nature of the fluctuations, but these characteristics did not differ between the tumors of C3H versus nudes in our study: mean (SD) tumor size was 270 (88) mm3 vs. 292 (61) mm3 and SMA expression was 0.77 (0.36)% vs. 0.56 (0.58)% in C3H vs. nudes, respectively.