Familial Risk of Hematologic Malignancies: a Twin Study

In this project, we set out to study the hypothesis that tattoo ink, which is known to migrate to regional lymph nodes, induce inflammation at deposit site which may eventually become chronic and increase risk of hematopoietic cancer cell formation. First, we study etiology of hematologic malignancies through the Nordic Twin Cancer Study. We verify previous findings of familial predisposition and provide novel information on the influence of genetic and environmental factors by age. As a link between environmental exposures and the effect they have on our genes, we conduct an epigenome-wide association twin study of DNA methylation and hematopoietic malignancies identifying 67 CpG biomarkers of which 12 are linked to genes associated with hematologic malignancy. Further, we set up a predictor performing persistently at a high level up to six years after blood sampling. 

Moreover, we establish the Danish Twin Tattoo Cohort which has so far enabled two studies and may become an important source of knowledge in the field. First, in a study of tattooing determinants, we provide empirical evidence of the dramatic increase in cumulative incidence of tattooing over the past decade, find that tattooing behavior is a cultural group clustering phenomenon with limited genetic influence, and detect a strong association between smoking and tattooing. Second, we examine the hypothesized risk factor, tattooing, and provide novel evidence associating tattoo exposure with increased risk of lymphoma and skin cancer. These findings are of great importance in a world where tattooing has become immensely popular and knowledge on the long-term safety has been found sorely lacking. It is our hope that further knowledge will be pursued for the benefit of public health and health science.