CRP and esophageal squamous cell carcinoma: For example, in thoracic ESCC patients, one study found that performance status, initial weight loss, lymph node stage, and serum C-reaction protein (CRP) level, cigarette smoking, and differentiation grade were related to prognosis [18]; and another reported that swallowing difficulty, cigarette smoking, number of invasive lymph nodes, and gastric cardia involvement were independent prognostic factors [19].