ESR1 and breast cancer: The induction of splice variant PPARγ1b is in agreement with previous in vitro studies that demonstratedactivation of PPARγ1 by the endocrine disruptor monoethyl-hexyl-phthalate in C2C12 mouse skeletal muscle cell line [2],and with MCF-7 breast cancer cells stimulated with E2, the natural ERα ligand [38].