RHD and esophageal squamous cell carcinoma: The distribution of blood groups in the esophageal squamous cell carcinoma patients (n = 480) was 98 (20.4%) blood group A, 58 (12.1%) blood group AB, 226 (47.1%) blood group B, and 98 (20.4%) blood group O. Rh status was positive in 424 (88.3%) and negative in 56 (11.7%) patients (Table 1).