ESR1 and neoplasm: Mutually adjusting and adjusting for baseline age class, year, month, patient ID, municipality of residence, and tumor morphology, the fixed effects variables associated with lower death rate were ER+ and/or PR+ (HR 0.61, 95% CrI 0.45–0.81) and HER2/neu + (HR 0.59, 95% CrI 0.44–0.79).