Tumor suppressor gene PTEN and cyclooxygenase

??Expression and Significance of Tumor Suppressor Gene PTEN and Cyclooxygenase2 in Colorectal Cancer ??
To detect the expression of tumor suppressor gene PTEN and cyclooxygenase2 (COX2) in colorectal cancer? and analyze their significance. Methods SP immunohistochemical method was used to detect the expression of PTEN and COX2 in 10 cases of normal colorectal membrane and 80 cases of colorectal cancer. Results The expression of PTEN in all of the normal colorectal membrane were positive? and expression of PTEN in 41.2% cases of colorectal cancer were low or negative? which was much lower than the normal group(P

??Key words: PTEN; COX2; Colorectal carcinoma

??Colorectal cancer is one of the most common malignant tumors in China, for their research on canceration mechanism has been hot spot. Tension of tumor suppressor genes and protein phosphatase gene homologous 10Q lost (Phosphatase and tensin homology deleted on chromosome10,PTEN) closely related to the occurrence, development of various tumors, in the large intestine also found to have abnormal expression of PTEN gene. Cyclooxygenase 2 (Cyclooxygenase2,COX2) expression in many tumors are high and closely related to the formation of tumors, but the mechanism is unclear. This article intended by detecting expression of PTEN in carcinoma of large intestine and COX2, and explore the relationship between the two.

??1 materials and methods

??1.1 specimen sources collected affiliated hospital of Guangdong Medical College from 1996 to 2004 and biopsy specimens a total of 90 cases of colorectal surgery (are not trained in patients before chemotherapy, radiotherapy), of which 10 cases in normal colon mucosa, 80 cases of Carcinoma of large intestine, which differentiate 30 cases, differentiation in 27 cases, poorly differentiated 23 cases, 35 patients with lymph node metastasis. All specimens are fixed with formalin 10%, conventional paraffin, 4 ? m serial sections, after HE dyed, and confirmed by pathology experts.

??1.2 main one PTEN monoclonal antibody reagents mice (work), rabbit anti-human COX2 (concentration, concentration of 1:100), SP immunohistochemical reagent cartridge color liquid and DAB were purchased from Beijing Zhongshan biotechnology co., Ltd.

??1.3 all specimens are the experimental methods with formalin fixed, conventional paraffin, 4 ? m serial sections, General dewaxing, gradient of alcohol to the water of hydration, microwave repair, natural cooling to room temperature. Using the immunohistochemical SP method stain, color 3 DAB min~5 min, complex dye hematoxylin 5 min, differentiation of hydrochloric acid alcohol seconds, running water returned to blue-15 min, gradient alcohol dehydration, DPX, neutral gum tablet. Replaced by PBS as blank control resistance, known to be positive for positive control. In an optical microscope observation.

??1.4 judgment PTEN and COX2 positive immunohistochemical results are positioned in the cytoplasm and cell membrane, is yellow or brownish yellow particles. Double blinding statistical results. Random select 10 high view count, count the percentage of positive cells, according to the proportion of positive cells are divided into the following four levels: 50% to strongly positive (+++).

??1.5 statistics SPSS12.0 statistics analysis software package, rate comparison using ? 2 tests, correlation using Spearman rank correlation analysis, test standards take two-sided ? = 0.05.

??2 results

??2.1 expression of PTEN in Colorectal, see table 1.

??Expression of PTEN in Colorectal carcinoma in table 1 (omitted)

??Note: compared with the normal group, P ??
??PTEN expression in normal colon mucosa are strongly positive, while in 33 cases lack PTEN protein expression in Colorectal (negative group) or reduce (weakly positive), 41.2%, significantly lower than its expression in normal colon mucosa (? 2=20.911,P=0.0000.05).

??2.2 in the case expression in carcinoma of large intestine, as shown in table 2.

??Table 2 x expression in colorectal cancer (omitted)

??* Note: compared with the normal group, P ??
??COX2 is mainly dominated by negative expression in normal colon mucosa, (80%), in the positive rate of colorectal cancer in the (72.5%), significantly higher than their expression in normal colon mucosa (? 2=13.163,P=0.0040.05).
2.3 PTEN, COX2, and metastasis of lymph node metastasis of Carcinoma of large intestine without positive expression rate of PTEN in carcinoma of large intestine (86.7%), and positive expression rate of transfer (74.3%), lower than the former (? 2=8.082,P=0.044

??Table 3 metastasis of Carcinoma of large intestine and PTEN, COX2 (omitted)

??* Note: compared with no transfer group, P

??2.4 PTEN in carcinoma of large intestine and correlation of COX2 Spearman rank correlation analysis, PTEN in Colorectal and COX2 negative correlation (correlation coefficient r=-0.215,P=0.042

??3 discussion

??PTEN gene in 10 q 23.3, encoding consists of 403 amino acid protein [1]. Research has shown that the protein has the double lipid phosphatase, protein phosphatase activity, can make the second Messenger phosphorylation of PIP3, interrupting its downstream activation of Akt kinase, thus blocking the corresponding signal transduction system, thereby inhibiting cell growth [2]. PTEN and multiple type malignant tumor of occurred and development is closely related to, this research found PTEN in normal colorectal mucosa in the are for strong positive expression, and in large colorectal cancer in the negative and weak positive expression of accounted for 41.2%, and normal group compared differences has significantly statistics significance (P

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