CCND1 and esophageal squamous cell carcinoma: Although the expression of cyclin D1 alone was not associated with ESCC prognosis in our study, our results suggest that cyclin D1 may be a key factor in the MACC1/c-Met signaling pathway, and the combined expression with MACC1 and c-Met may serve as a new esophageal research idea for prognosis of patients with squamous cell carcinoma.