AIM: To investigate the effects of inhibiting factor of cellcycle regulation p57kip2, retinoblastinoma protein (Rb protein)and proliferating cell nuclear antigen (PCNA) in the genesisand progression of human pancreatic cancer.METHODS: The expression of p57kip2, Rb protein and PCNAin tumor tissues and adjacent tissues of 32 patients withpancreatic cancer was detected with SP immunohistochemicaltechnique.RESULTS: p57kip2 protein positive-expression rate in tumortissues of pancreatic cancer was 46.9 %, which was lowerthan that in adjacent pancreatic tissues (75.0 %) (x2=5.317,P＜0.05), p57kip2 protein positive-expression correlatedsignificantly with tumor cell differentiation (well-differentiationversus moderate or low-differentiation, P＜0.05) but did notcorrelate significantly with lymph node metastasis (lymph nodemetastasis versus non-lymph node metastasis, P＞0.05); Rbgene protein positive-expression rate in tumor tissues was50.0 %, which was also lower than that in adjacent pancreatictissues (78.1%) (x2=5.497, P＜0.05); PCNA positive-expression rate was 71.9 %, being higher than that inadjacent pancreatic tissues (43.8 %) (x2=5.189, P＜0.05),PCNA positive-expression also correlated significantly withtumor cell differentiation and lymph node metastasis (well-differentiation versus moderate or low- differentiation, lymphnode metastasis versus non-lymph node metastasis, P＜0.05).Rb protein positive-expression rate in the tumor tissues ofp57kip2 protein positive-expression group was 53.3 %; andRb protein positive-expression rate in the tumor tissues ofp57kip2 protein negative-expression group was 47.1%. Therewas no significant relationship between the two groups(r=0.16507, P＞0.05).CONCLUSION: The decreased expression of p57kip2, Rbprotein or over-expression of PCNA protein might contributeto the genesis or progression of pancreatic cancer, p57kip2,Rb protein and PCNA may play an important role in genesisand progression of pancreatic cancer.