ANCOVA showed that the difference in WBC counts between patients and matched controls was significantly greater for premenopausal non-obese women with ER+/PR+ breast cancer than for those with ER−/PR− breast cancer or ER+/PR− or ER−/PR+ breast cancer (p = 0.020 and p = 0.038, respectively). The gene discussed is ESR1; the disease is breast cancer.