Molecular-target therapies are novel approaches to the treatment of prostate and ovarian cancer, but to ensure the best response, a very careful selection of patients, based on immunological characteristics, must be performed. We screened for HLA type, 24 patients with advanced ovarian cancer and 26 patients with hormone-refractory prostate cancer, in order to be recruited to vaccine protocols. HLA typing was performed with PCR in ovarian cancer patients and with serological assay in prostate cancer patients. The results were then extended to a population level, comparing the HLA genotype frequencies in Europe with ovarian and prostate cancer mortality rates. An overrepresentation of HLA-A2 phenotype was observed in both patient groups compared to the normal Swedish population (p = 0.01). As it is already known, the higher phenotype frequency of this allele found in Scandinavian countries decreases significantly as one moves further south in Europe. Ovarian and prostate cancer mortality rates decrease as well as the demographic changes in HLA-A2. These observations have to be confirmed by more extended investigations in order to elucidate if HLA-A2 higher frequency is already present at the diagnosis (risk factor) or is selected during the course of the disease (prognostic factor). Moreover, this fact would suggest different strategies for specific immunotherapy in addition to first line conventional treatments.