This mechanism for the regulation of FOXM1 expression means that any drug resistance mechanism that results in sustained PI3K signaling will lead to persistent FOXM1 expression following drug treatment and, since in ER+ breast cancer cells FOXM1 drives expression of LDHA, will lead to sustained exchange of hyperpolarized 13C label between pyruvate and lactate. The gene discussed is PIK3CB; the disease is breast cancer.