Published by admin at August 15, 2017 Is smoking the main reason for cancer or not Macnair, P. Smoking-health risk-Netdoctor.†www.netdoctor.co.uk/healthadvise/facts/smokehealth.htm * Whitehead, C. Two main causes of cancer.†eHow http://www.ehow.com/about_5300805_two main-causes-cancer.htm