The most frequently diagnosed cancer of the female genital tract is cancer of the endometrium (endometrial cancer), ranking fourth among the invasive tumors that affect women in Europe and North America. As most other cancer types, endometrial cancer is a complex genetic disease influenced by both genetic and environmental factors.

The human population is genetically heterogeneous and studies of complex diseases in human are proven to be difficult. By using a model system such as the BDII rat, some of the obstacles related to the study of complex diseases can be avoided. The BDII rat strain is prone to spontaneously develop endometrial adenocarcinoma (EAC) and more than 90% of the virgin females develop EAC during their lifetime. Development of EAC tumors in BDII rats is comparable in pathogenesis and histopathological properties to that of human.

The aims of this thesis were i/ to characterize EAC in the BDII rat experimental model system by analyzing structural and numerical chromosome aberrations, ii/ to evaluate the importance of the genetic set-up in EAC development, and iii/ to determine the impact of genomic and genetic alterations on the functionality of candidate genes in rat EAC and in human endometrial tumors of different FIGO grades.

Non-random numerical and structural aberrations that could contribute to tumor formation were identified, and evidence that the genetic background had a significant influence on the genome make-up of tumor cells was provided. Certain genes (Gpx3/GPX3, Met/MET, Phf5a/PHF5A, and Gja1/GJA1) were selected for further analysis and aberrant expression of some of them were found in both rat and human EACs. By separating EAC cell lines according to the genetic cross background, for two of the genes (Phf5 and Met), we showed that the expression pattern differed significantly between different cross backgrounds, which clearly pinpoint the importance of using animal models as a complement to clinical studies in identification of cancer-related genes.