PAX7 and neoplasm: However, we found, for the first time, that voluntary physical activity per se did not induce a significant increase in the expression of Pax7 (Figures 4(a) and 4(b)) and MyoD (Figures 4(c) and 4(d)), albeit it specifically downregulated Pax7 expression in the musculature of tumor-bearing mice, likely releasing a block to muscle regeneration (Figures 4(a) and 4(b)).