Studies have found that CHOP, commonly used as a marker of endoplasmic reticulum (ER) stress, has predictive value in breast cancer patients receiving adjuvant chemotherapy, and CHOP is associated with prolonged disease-free survival (HR = 0.385, 95% CI 0.215–0.688; P = 0.001) [30]. The gene discussed is DDIT3; the disease is breast cancer.