PER2 and breast cancer: According to these original data, TWIST1 emerges as a central player in doxorubicin-treated breast cancer cells, since some of the upstream regulators of TWIST1 (PTEN, Akt, IGF, p70S6K, c-Myc, TIMELESS, miR-29a, miR-34a, miR145) and dowstream effectors (GLI1, Survivin, p21, Bcl-2, Bax, VEGFa, SLUG1, Per1, Per2, miR-10b) have all been found altered upon doxorubicin treatment.