THE STUDY ON RELATIONSHIP BETWEEN CIGARETTE SMOKING AND THE p53 PROTEIN AND P21 PROTEIN EXPRESSION IN NON-SMALL LUNG CANCER

This paper discusses the relationship between cigarette smoking and the p53 protein and P21 protein expression by the immunohistochemical analysis in 93 cases with lung cancer in which squamous cell carcinoma accounted for 45 cases, adenocarcinoma 48 cases. The results showed that positive proportion of p53 protein expression was 74.20% (28 of 37 squamous cell carcinoma, 21 of 30 adenocarcinomas) in cigarette smoking group with lung cancers, and 38.46% (3 of 8 squamous cell carcinoma, 7 of 18 adenocarcinomas) in nonsmoking group with lung cancers. The difference was statistically significant. Odds ratio was 4.14 and confidence limits for OR was 1.42-12.52. A dose-related presents in the p53 protein expression for the smoking amount and smoking years. The positive proportion of P21 protein expression was 79.31% (21 of 28 squamous cell carcinoma, 25 of 30 adenocarcinomas) in cigarette smoking group with lung cancers, and 82.75% (10 of 11 squamous, 14 of 18 adenocarcinomas) in nonsmoking group with lung cancers, the difference was not statistically significant. But their positive proportion of P21 protein expression were very high in both groups. It was indicated that no relationship between cigarette smoking and the P21 protein expression. We suggest that the p53 gene could be a common target of tobacco-associated carcinogenesis in lung cancer.

Study on the p53 Protein Expression in Gastric Cancer and Precancerous Lesions by Flow Cytometry

At present, p53 gene and its product p53 protein are the hot spot in the field of cancer research. 50% human malignant tumors are associated with p53 alteration. p53 gene mutation is the most common mutation, which can lead to regulation disturbance of cell proliferation. Gastric cancer is the most common disease in China. Its incidence is the second among various malignant tumors.There were reports about p53 protein expression and gastric cancer progression but few report on p53 protein expression in different stages of precancerous lesions was available. In this study,we analyzed p53 protein expression in gastric cancer and precancerous lesions by flow cytometry to evaluate the role of p53 protein in the pathogenesis of gastric cancer.

Oncoprotein expression and inhibition of apoptosis during colorectal tumorigenesis

AIMS To study bcl-2 and P53 protein expression and inhibition of apoptosis during colorectal tumorigenesis. METHODS Expression of bcl -2 and p53 in 45 colorectal ade- nomas and 61 colorectal carcinomas was detected by immunohis- tochemical staining. RESULTS The bcl-2 and P53 protein expression was uniformly negative in normal mucosa,whereas bcl-2 and p53 positive rates were significantly higher in adenoma and carcinoma than in nor- reals(P<0.01 ).The area with strong bcl-2 expression was of- ten the area with severely dysplasia.In colorectal adenoma,ex- pression of p53 increased with the increasing size and dysplasia, in adenomas≥20 mm being higher than adenomas<10 mm(77, 8% vs 35.0%,P<0.05).p53 was relevant to differentiation and Duke's staging.A significant inverse correlation was found between bcl-2 and p53 in immunostaining in the adenomas,but not in the carcinomas.Furthermore,carcinomas with a high per- centage of bcl-2 positive cells were significantly more likely to have low rates of apoptosis. CONCLUSIONS These results suggest that bcl-2 gene appears to be an early event in colorectal tumorigenesis that can inhibit apoptosis,p53 expression plays an important role in the develop- ment and malignant change of colorectal adenoma,bcl-2 and p53 may be used as a good marker relating to cell apoptosis.

QUANTITATION OF P53 PROTEIN EXPRESSION IN GASTROINTESTINAL SMOOTH MUSCLE TUMORSCLINICOPATHOLOGICAL CORRELATION AND PROGNOSTIC SIGNIFICANCE

Quantitative analysis of P53 protein expression was performed on paraffin-embedded tissues from 55 smooth muscle tumors of the gastrointestinal tract, using immunofluo-rescence and flow cytometry. No positive expression was found in normal smooth muscle tissues of the gastrointestinal tract. Over-expression of P53 gene was found in a significantly higher proportion in leiomyosarcomas (90%) and potentially malignant smooth muscle tumors (75%) as compared to leiomyomas (14%) (P< 0.005). The quantitation of P53 expression was found to be progressively enhanced in the sequence from leiomyoma through potentially malignant smooth muscle tumor to leiomyosarcoma (P< 0.005). It was markedly over-expressed when the mitotic counts ranged from one to more than one per 10 high power fields (P< 0.005) or the mild cytologic atypia was found (P< 0.005). The five-year survival rate was significantly higher in patients with low-expression of P53 than in those with over-expression of P53 (P< 0.005). It was suggested that P53 over-expression might be associated with the transformation of leiomyoma into leiomyosarcoma and could be used as an objective parameter in distinguishing the malignant from the benign and predicting the prognosis of patients with smooth muscle rumors of the gastrointestinal tract.