Orho-Melander M, et al. - This study was performed to determine whether or not there are causal associations between blood lipids, the HMGCR gene, and cancer risk. Indeed, a causal and negative association between serum triglycerides and risk of any cancer under the assumptions of Mendelian randomization was shown. Further, the HMGCR genetic variant was correlated with risks of prostate and breast cancers, but the biological mechanisms underlying these findings were unclear, as the lipoprotein cholesterol (LDLC) instrumental variable (IV) was not associated with these cancers.