Single nucleotide polymorphisms of the FTO gene and cancer risk: an overview

The FTO (fat mass and obesity-associated) gene has a strong linkage disequilibrium block, within which SNPs have been identified that are involved in the development of obesity. Recently some of these variants have also been associated with cancer. However, identification of the possible mechanisms that could explain these associations has proven to be elusive. It has been found that FTO polymorphisms can regulate the expression of genes at large kilobases of distance as well as the expression of the FTO gene itself, and regions for transcription factor binding. To date it has been observed that variants rs9939609, rs17817449, rs8050136, rs1477196, rs6499640, rs16953002, rs11075995 and rs1121980 are associated with the risk of developing cancer. Some studies have produced negative results when comparing the same polymorphisms, but make a simple association between polymorphic variants and cancer, have proved difficult because this relation is by nature multifactorial. A certain degree of variation resulting from the improper design of studies or processing of data can lead to erroneous conclusions. However, it is now unquestionable that certain FTO polymorphisms regulate genetic expression related to cancer susceptibility, although this field is just beginning to be understood.