Low Dose TamOxifen and LifestylE Changes for bReast cANcer prevenTion

Circulating levels of Sex Hormone Binding Globulin (SHBG) are significantly associated with a decreased risk of breast cancer. The main aim of this clinical trial is to verify whether Low Dose Tamoxifen (LDT) increases circulating levels of SHBG more than lifestyle intervention (LI) with or without intermittent caloric restriction (ICR) after 6 months in women at increased risk of breast cancer (i.e., healthy participants carriers of a germline pathogenic/likely pathogenetic variant in at least one of the following genes: BRCA1, BRCA2, PALB2, ATM, CHEK2, CDH1, RAD51C or RAD51D, or with \> 5% breast cancer risk at 10 years, using the Tyrer Cuzick or the Breast Cancer Surveillance Consortium Risk models or with a recently resected intraepithelial neoplasia of the breast (IEN). The secondary aims are: * to verify whether ICR significantly modulates primary and secondary endpoints such as Homeostasis Model Assessment (HOMA) index, immune and inflammatory markers, lipid profile, Adiponectin/Leptin (A/L) ratio, quality of life (QoL), Body mass index (BMI), fat body composition, safety and toxicity; * to verify whether LDT significantly modulates secondary endpoints, such as HOMA-index, immune and inflammatory markers, lipid profile, A/L ratio, QoL, BMI, fat body composition, safety and toxicity; * to investigate differences in microbiome composition by arms and the effect of changes in microbiome on QoL taking into account circulating biomarkers, cytokines, immune modulators, and inflammatory proteins in serum; * to investigate MD (Mammographic Breast Density) changes by LDT vs. LI, with or without ICR. This aim will be performed in a subgroup of participants (not all the participants will undergo mammography due to younger age).