[9] The ratios of XBP1s/XBP1u mRNA (indicating enhanced splicing by IRE1) in 100 primary breast cancer patients who received tamoxifen treatment were measured by quantitative RT-PCR, and the result suggests that higher ratios of XBP1s/XBP1u are correlated with poorer survival [10]. The gene discussed is ERN1; the disease is breast cancer.