Clinical Analysis According to p21(Waf1/Cip1) and p27(Kip1) Expression in Gastric Cancer

ABSTRACT

PURPOSE: The p21(Waf1/Cip1) protein inhibits the cell cycle by inhibiting the phosphorylation at the G1-->S check point, and the p27(Kip1) protein similarly performs the suppressor function by controlling the p27-mediated G1 arrest. In this study, we analysed the clinical status and survival rates in correlations with p21 and p27 expression patterns in gastric cancer. MATERIALS AND METHODS: Between 1993 and 1997, 192 patients who underwent surgeries in Catholic Medical Center were analysed retrospectively in this study. Immunohistochemical staining was performed and if the nuclei of the tumor cells were stained, we assumed those as positive results. Statistical analysis was based on clinicopathological findings and differences in survival rates. RESULTS: The expression rate of p27 was 28.1% and 15.6% in p21 each. The ratio of T1-2(80.0%) was significantly high in p21 (+), but the ratio of T3-4 (50.6%) was slightly high in p21 (-). There was no statistical significance regarding other factors. The results in p27 was not much different from expression rate of p21 in T-stage. In addition, p27 expression in diffuse type (91.3%) was higher than in intestinal type (62.7%) by Lauren's classification (P <0.05). Also, there was no statistical significance in other factors. In the correlation of p21 and p27, p27 was positive when p21 was positive (53.5%). Conversely, p27 was negative when p21 was negative (76.5%, p <0.05). In the p21 and p27 combination test, there was higher rate of T1-2 (87.5%) in p21 (+)/p27 (+), and higher rate of T3-4 (58.1%) in p21 (-)/p27 (-) (P <0.05). Results showed higher rate of intestinal type (100%) in p21 (+)/p27 (+), and diffuse type (87.0%) was dominant in p21 (-)/p27 (-) (P <0.05) by Lauren's classification. Moreover, there was no statistical significance in the 5-year survival rate in the expression of p21 and p27, and the 5-year survival rate was highest in the case of p21 (+)/p27 (+) without statistical significance. CONCLUSION: In our study, p21(Waf1/Cip1) and p27(Kip1) expressed similar patterns. The expression of p21(Waf1/Cip1) and p27(Kip1) affected the degree of invasiveness of the tumor, and. Combined examination result revealed the correlation of p21(Waf1/Cip1) and p27(Kip1) with Lauren's classification and depth of invasion of the tumor. However, we assumed that little difference between the survival rates depending on expression of p21(Waf1/Cip1) and p27(Kip1) has limited their value as predictable prognostic indicators.