HMOX1 and cancer: In addition to causing cell cycle arrest, PL has been shown to induce cancer cell death through a variety of mechanisms including decreased DNA binding activity of the pro-survival transcription factor NF-κB in non-small cell lung cancer [37], activated MEK/ERK signaling in colon cancer cells [38, 39], elevated HO-1 via Nrf-2 signaling in breast cancer [40], and modulated JNK and PARP pathways in head and neck cancer [41].