Association of p53/p21 expression with cigarette smoking and prognosis in esophageal squamous cell carcinoma patients

factors,such as cigarette smoking,in esophageal squamous cell carcinoma(ESCC)in northeastern Iran,a region with a high incidence of ESCC.METHODS:The expression of p53 and p21 proteins was investigated immunohistochemically in tumor tissue from 80 ESCC patients and in 60 available paraffinembedded blocks of adjacent normal specimens from the cases,along with normal esophageal tissue from 80 healthy subjects.RESULTS:Positive expression of p53 protein was detected in 56.2%(45/80)of ESCC cases,and in none of the normal esophageal tissue of the control group(P<0.001).Furthermore,73.8%(59/80)of ESCC cases and 43.8%(35/80)of controls had positive expression of p21 protein(P<0.001).Cigarette smoking was significantly associated with p53 over-expression in ESCC cases(P=0.010,OR=3.64;95%CI:1.32-10.02).p21 over-expression was associated with poorer clinical outcome among the ESCC patients(P=0.009).CONCLUSION:Over-expression of p53 in association with cigarette smoking may play a critical role in ESCC carcinogenesis among this high-risk population of northeastern Iran.Furthermore,p21 over-expression was found to be associated with poor prognosis,specifically in the operable ESCC patients.