Traditional and new diagnostic and prognostic markers in breast cancer

Despite the constant progress on the understanding of the molecular bases of cancer, there is still the need to identify novel prognostic and predictive markers aimed at improving diagnosis and, at the same time, designing a more targeted therapeutic approach. For this to be achieved, we have to take into consideration the biological heterogeneity of each tumor that explains different responses to standard therapies harbored by different patients within the same tumor stage and histological type. Such a combined approach does not apply to improving classification and prognosis of breast cancer only, but it is widely applicable to a better understanding and treatment of all cancers. Nevertheless, it is also crucial to bare in mind that cancer is a genetic disease and molecular analyses aimed at unravelling genetic make-up of tumors are of extreme importance. However, the contribution of the environment in the development of a neoplastic disease should not be ignored, as this would also provide useful insights for cancer prevention. Exposure to harmful substances (i.e. X-rays, UV-light, carcinogens just to list some examples) and to pathogens which might be endemic in some areas could also contribute to triggering genetic alterations whose accumulation may result in malignant transformation, and should not be ignored when trying to understand the etiology of certain tumors. The aim of this thesis is to provide evidence of how novel genetic markers may contribute to a better classification and diagnosis of cancer, using as examples studies conducted on breast cancer and lymphoma. Also, reactivation of the Epstein-Barr virus due to exposure of unfavorable environmental conditions is provided in another study, to highlight the tremendous importance of the environment in the development of cancer, which is too often dismissed in both the anamnesis of cancer patients and in research studies.