ESR1 and breast neoplasm: Cox proportional hazard analysis of the three cohorts revealed that patients with breast tumours overexpressing FMR1 mRNA have an increased risk to develop lung metastasis (hazard ratio (HR) = 1.21; 95% CI 1.02–1.45, p = 0.0293) and this is independent from estrogen receptor status (HR = 1.51 95% CI 1.27–1.85, p < 0.0001), the only pathological parameter available for all datasets considered.