Background: To improve the prognosis of gallbladder cancer (GC) patients, a better understanding of the mechanisms of tumor development and progression is essential. The deregulation of cell cycle control is a critical step in the development of cancer. The purpose of this study was to investigate the expression of p21(Wafl/Cip1), p57(Kip2) and HER2/neu in an unselected GC patient population and to assess the association of these markers with p27(Kip1) expression, p53 gene mutation status and clinical parameters of the patients.
Patients and methods: Formalin-fixed paraffin-embedded tissues from 55 operated GC patients were used to determine the expression of p21(Wafl/Cip1), p57(Kip2) and HER2/neu with immunohistochemistry.
Results: Expression of p21(Wafl/Cip1) was observed in 28%, of p57(Kip2) in 19% and of HER2/neu in 13% of the patients. Absence of p57(Kip2) expression was significantly associated with T3/T4 stage (p = 0.01), positive lymph nodes (p = 0.02) and advanced UICC stages (p = 0.05). HER2/neu expression significantly correlated with advanced T stages (p = 0.02). In the total patient population, p21(Wafl/Cip1), p57(Kip2) and HER2/neu had no impact on survival of the patients. Among patients with a mutated p53 gene, those without p21(Wafl/Cip1) expression had a prolonged survival compared to patients with p21(Wafl/Cip1) expression (p = 0.004). Moreover, in p27(Kip1)-positive patients, those without p21(Wafl/Cip1) expression had a longer survival than those with p21(Wafl/Cip1) expression (p = 0.003).
Conclusion: In the subgroup of patients with a mutated p53 gene or in p27(Kip1)-positive patients, absence of p21(Wafl/Cip1) expression may be associated with longer survival of GC patients. Therefore, further analyses of this protein in larger patient populations are warranted.