Cancer is a complex disease caused by both genetic factors and non-genetic factors, such as diet, obesity, and lifestyle factors. To date, several meta-analyses of genome-wide association studies (GWAS) have been carried out and these studies have uncovered many genetic variants associated with different cancers. Large GWAS consortia are available on common cancers, including prostate cancer (Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome consortium) (1), breast cancer (Breast Cancer Association Consortium) (2), ovarian cancer (Ovarian Cancer Association Consortium) (3), endometrial cancer (Endometrial Cancer Association Consortium) (4), and colorectal cancer (e.g., the Colorectal Transdisciplinary Study) (5). The Swedish Mammography Cohort and Cohort of Swedish Men are included in these consortia. GWASs on other cancers, such as pancreatic, bladder, and blood cancers (i.e., multiple myeloma, non-Hodgkin’s lymphoma, Hodgkin’s lymphoma, and leukemia) as well as overall cancer are either lacking or based on small sample sizes. Therefore, large-scale GWASs are warranted to explore the genetic architecture of these less common cancers.