Many studies have been conducted to examine the association between BRCA1 polymorphisms and the risk of various cancers, including breast cancer, ovarian cancer (OC), cervical cancer, ESCC, gastric cancer, chronic myeloid leukemia (CML), and NHL [14–32]; however, the results remain inconsistent or even contradictory. The gene discussed is BRCA1; the disease is esophageal squamous cell carcinoma.