STAT3 and cancer: The expression levels of B-cell lymphoma 2 (Bcl-2) that inhibits apoptosis in cancer cells, signal transducer and activator of transcription 3 (STAT3) that promotes cancer cell generation and tumor proliferation, and matrix metalloproteinase-9 (MMP-9) that is involved in cancer cell metastasis in skin cells were often measured to confirm the anticancer activities of the extracts from natural resources [13–15].