TNM stage still serves as the best prognostic marker in
gastric cancer (GC). The next step is to find prognostic
biomarkers that detect subgroups with different prognoses in the same TNM stage. In this study, the expression levels of
epidermal growth factor receptor (EGFR) and
cyclin D1 were assessed in 96 tissue samples, including non-tumorous tissue,
adenoma, and
carcinoma. Then, the prognostic impact of EGFR and
cyclin D1 was retrospectively investigated in 316 patients who underwent R0 resection for GC. EGFR positivity increased as gastric tissue became malignant, and
cyclin D1 positivity was increased in all the tumorous tissues. However, there was no survival difference caused by the EGFR positivity, while the
cyclin D1-postive group had worse overall survival (OS) than the
cyclin D1-negative group in stage I GC (10-year survival rate (10-YSR): 62.8% vs. 86.5%, p = 0.010). In subgroup analyses for the propensity score-matched (PSM) cohort, there were also significant differences in the OS according to the
cyclin D1 positivity in stage I GC but not in stage II and III GC. Upon multivariate analysis,
cyclin D1 positivity was an independent prognostic factor in stage I GC. In conclusion,
cyclin D1 may be a useful
biomarker for predicting prognosis in stage I GC.