Retrospective survival studies in archive tissue.

There is a lot of criticism in literature about clinical retrospective studies, but these studies can be improved by a better design and a better selection of cases. The second problem of these studies, partially in common also with the prospective ones, is the selection of tissues and their microdissection related to the high level of heterogeneity usually found in tumours. This is also related to lack of standardization of the molecular methods used in archive tissues, starting from extraction of nucleic acids. Only with a correct microdissection and with stardardized methodologies it is possible to obtain reproducible results that can be informative for clinical development. These archive tissues will be increasingly important in the future to better subgroup therapy patients, to recognize new acquired resistance biomarkers, to establish the real efficacy of the new therapies. Today the major European organizations are starting to improve the quality of these studies with specific working groups and increasing the collaboration with the already developed biobanking system in Europe (BBMRi).