QE could induce apoptosis in human lung adenocarcinoma cell line A549 through mitochondrial depolarization by down-regulating the interleukine-6/signal transducer and activator of transcription 3 (IL-6/STAT3) signaling pathway [7], and QE could also inhibit the proliferation of cancer cells by regulating the phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) and epidermal growth factor receptor (EGFR) signaling pathway [8,9,10]. Here, STAT3 is linked to cancer.