The Expression Of HMSH2,hMSH6 And PCNA In Non-small Cell Lung Cancer

Objective:Lung cancer is a major public health problem worldwide, with the morbidity and the mortality of the disease approaching the highest rank. The five-year survival rate of patients with the early stage of lung cancer is definitely higher than that with the late stage. Due to the lack of the valid diagnosis methods of the early-onset lung cancer, unfortunately most patients were diagnosed at late stage. The diagnosis of early NSCLC relies on the understanding of the pathogenesis of the disease. The pathogenesis of NSCLC has not been very clear, therefore the potential clinical applications of predictors are rare. Base-base mismatch must arise during the proliferation and DNA replication. Mismatch repair (MMR) system is very important to recognize and repair the base-base mismatches in maintaining stability of cellular genetics. The hMSH2 and hMSH6 proteins are components of the DNA mismatch repair system, which can recognize and bind mismatched bases that may have occurred during DNA replication. The function of proliferating cell nuclear antigen (PCNA) as a protein plays a key role in process of DNA replication. This study attributed to understand the pathogenesis and help the early diagnosis of the disease by detecting the expression of hMSH2,hMSH6 and PCNA in NSCLC.Methods:NSCLC tissues with clear pathological diagnosis from 96 patients with 32 adjacent tissues were collected. Immunohistochemistry was used to detect the protein expressions of hMSH2,hMSH6 and PCNA in these tissues. SPSS11.5 statistic software was used to analyze the correlation of their expressions to the clinical characteristics in NSCLC tissues.Results:In NSCLC tissues and adjacent tissues, the positive rates of hMSH2 protein expression were 51.6%(49/96) and 15.6%(5/32) respectively, which in the former was significantly higher than that in the latter(P<0.05), the positive rates of hMSH6 protein expression were 75.0%(72/96) and 68.8%(22/32) respectively, there was no significant difference between the two groups(P>0.05), while the positive rates of PCNA protein expression were 83.3%(80/96) and 12.5%(4/32) respectively, which in the former was significantly higher than that in the latter(P<0.05).In NSCLC tissues, the positive rates of hMSH2 protein expression in the well-moderately differentiated and the poorly differentiated adenocarcinoma were 39.6%(21/53) and 88.9%(8/9) respectively, there was significant difference between the two groups(P<0.05), the positive rates of hMSH6 protein expression in the well-moderately differentiated and the poorly differentiated adenocarcinoma were 66.7%(36/53) and 100.0%(9/9) respectively, there was significant difference between the two groups (P<0.05), while the positive rates of PCNA protein expression in squamous cell carcinoma and adenocarcinoma were 73.1%(19/26) and 90.3%(56/62) respectively, there was significant difference between the two groups (P<0.05). The expressions of hMSH2, hMSH6 and PCNA protein had no relationship with sex, age, size, location, lymph node metastasis, TNM stage, family history and smoking history(P>0.05).In NSCLC tissues, the hMSH2 protein expression had no clear correlation with PCNA (r=0.177, P>0.05); but the rates of hMSH6 protein expression significantly correlated with the levels of PCNA protein expression (r=0.258, P<0.05); the rates of MMR protein expression significantly correlated with the levels of PCNA protein expression (r=0.358, P<0.05).In adjacent tissues, the positive rates of hMSH6 protein expression were higher than that of hMSH2 protein expression.In NSCLC tissues and adjacent tissues, the total positive rates of hMSH2, hMSH6 and PCNA protein expression rates of cells were 39.6% (38/96) and 0.0%(0/32), there was significant difference between the two groups (P<0.05).Conclusions:1. The expressions of hMSH2 and PCNA protein were up-regulated in non-small cell lung cancer tissues. 2. The hMSH6 protein played a significant role in mismatch repair system of normal lung tissues.3. The expressions of hMSH2 and hMSH6 protein were up-regulated in the poorly differentiated adenocarcinoma, because of the cellular rapid proliferation.4. It may be helpful to detect the expressions of hMSH2, hMSH6 and PCNA for predicating the happening of NSCLC.