Although FAPs essentially promote more fibrotic tissue formation than adipose tissue in various myopathies (10, 11, 25, 26), we did not observe changes in collagen area as well as fibrosis markers such as protein levels of fibronectin and collagen I. Our results suggest that FAPs differentiate into adipose tissue rather than fibrotic tissue in patients with breast cancer who were treated with CT. This evidence concerns the gene FN1 and breast cancer.