1. Department of Biostatistics, The University of Texas School of Public Health, Houston, Texas, USA
2. Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas School of Public Health, Houston, Texas, USA
3. Department of Breast Medical Oncology, Division of Cancer Medicine, MD Anderson Cancer Center, Houston, Texas, USA
4. Department of Biostatistics, MD Anderson Cancer Center, Houston, Texas, USA