Several factors have been suggested to influence weight gain after diagnosis including age [10, 11, 13, 14], educational level [11, 13], initial Body Mass Index (BMI) [11, 13], physical activity [25], energy intake [9, 10], smoking status [10], menopausal status and hormone receptors’ status for breast cancer [10], disease stage [10, 13] and cancer-related treatments [8, 12–14, 26–29]. This evidence concerns the gene NR4A1 and breast cancer.