NR4A1 and breast cancer: However, in univariable analysis hormone receptor negativity was significantly associated with unfavourable prognosis only among the patients without BRCA1 mutations (HR = 0.18, 95% CI = 0.03 to 0.98, P = 0.04), whereas the impact of hormone receptor status on the prognosis of breast cancer among BRCA1 mutation carriers was not statistically significant (HR = 1.09, 95% CI = 0.21 to 5.67, P = 0.91).