1. Division of Experimental Therapeutics, Istituto Europeo di Oncologia, Milano, Italy
2. Division of Epidemiology and Biostatistics, Istituto Europeo di Oncologia, Milano, Italy
3. Department of Statistics and Quantitative Methods, University of Milan-Bicocca, Milano, Italy
4. Breast Cancer Program, Istituto Europeo di Oncologia, Milano, Italy