An immunohistochemical study of ras oncoprotein expression in gastric carcinoma

Characterization of oncogene suppressor marker expression in patients with submucosal gastric carcinoma

The aim of the present study was to determine the clinical significance of p53 and p21^ras p21^wafl, p27^kip1 and p16^ink4a expression in cases of early gastric cancer. A total of 81 patients who had undergone gastrectomy with D2 lymphadenectomy between 1971 and 2004 were retrospectively investigated. The immunohistochemical expression of p21^ras, p53, p21^waf1/cip1, p27^kip1 and p16^ink4a in the tissues was evaluated. In normal, metaplastic and tumoral mucosa, p53 was positive in 53, 87.3, and 87.1% of the cases, respectively. In the same tissues, p21^ras was positivE in 85.3, 86 and 96.8%, respectively. Positivity FOR p16^ink4a was DETECTED IN 46.3, 91.1 and 86% OF THE CASES, respectively, WHEREAS p27^kip1 WAS positiVE IN 60, 94.7 and 95.3%, and p21^wafl/cip1 WAS positivE IN 32.4, 72.7 and 71.4% OF THE CASES, respectively. All THE tumors WERE positive for p53. Tumors with lymph node invasion presented WITH OVERexpression (+4) of p53 in 47% of the cases VS. 17% OF patients who DID not HAVE lymph node involvement. THEREFORE, higher expression of p53, p21^ras and p21^wafl/cip1 IN the tumor exhibited a statistically significant association with lymph node involvement.

Regulative effect of traditional Chinese medicine on gene-expression related to precancerous lesion of gastric cancer

The gene-expression changes related with precancerous lesion of gastric cancer (PLGC) are surveyed. Not only the regulative effect of traditional Chinese medicine (TCM) on oncogene, antioncogene and anti-apoptosis gene that are related with PLGC is analyzed, but also current research state is presented. It's showed that TCM has effects of therapy and inversion on PLGC. These effects are related with the inhibition to related oncogene expression, the regulation and activation to the deletion of antioncogene, the inhibition to the high-expression of mutant gene-protein about antioncogene, and the regulative function to anti-apoptosis gene.

Diagnostic and prognostic tumor markers in the gastrointestinal tract

The gastrointestinal tract is the most common site of malignancies of any anatomic system in the body. An early detection of primary tumors of the bowel, pancreas, liver, stomach, and esophagus is often difficult in asymptomatic patients and for this reason these tumors are often detected at a relatively advanced stage, when symptoms lead to a diagnostic evaluation. Furthermore, gastrointestinal tract tumors have an extremely variable prognosis; thus, the identification of new prognostic parameters may be useful for selecting patients to more tailored therapies. In this work, the main molecular, genetic, tissular, and circulating tumor markers proposed for diagnosis and prognosis of gastrointestinal malignancies are reviewed and discussed.

Relationship of plasma folic acid and status of DNA methylation in human gastric cancer

To evaluate the anti-cancer effects of folic acid at the molecular level, we determined plasma folic acid concentration by radioimmuno-assay and the degree of total genomic DNA methylation by incubating DNA with 3H-S-adenosylmethionine (3H-SAM) in the presence of a methylase, and analyzed the methylation status of the c-myc and c-Ha-ras oncogenes by Southern blotting in 21 patients with advanced gastric cancer. The degree of total genomic DNA methylation of cancerous tissues was significantly lower than that of paracancerous and non-cancerous tissues; c-myc and c-Ha-ras oncogenes from cancerous (10/21, 5/10) and paracancerous (13/21, 4/10) tissues were hypomethylated. The plasma folic acid concentration in patients who showed hypomethylation was lower than that patients showing normal methylation. These findings suggest that a decrease in folic acid, and the subsequent DNA hypomethylation, may be involved in human gastric carcinogenesis.

Oncoproteins and tumor progression in papillary thyroid carcinoma: presence of epidermal growth factor receptor, c-erbB-2 protein, estrogen receptor related protein, p21-ras protein, and proliferation indicators in relation to tumor recurrences and patient survival

BACKGROUND

The prognostic relevance of activated oncogenes and oncoproteins has not been well studied in papillary thyroid cancer, which is slow-growing, with only regional spread in most cases. Therefore, the influence of some protein markers and tumor cell proliferation on disease progress in a series of patients with surgically treated papillary thyroid carcinoma was studied.

METHODS

One hundred twenty-seven patients with papillary thyroid carcinoma larger than 10 mm in greatest dimension were studied retrospectively, and the majority were treated with total or near-total thyroidectomy. Immunohistochemical and flow cytometric analyses of paraffin embedded tumor material were performed and the results were related to time to recurrence and thyroid cancer deaths using the univariate product-limit survival analysis and the multivariate Cox' regression method.

RESULTS

Immunohistochemical expression of c-erbB-2 protein, estrogen receptor-related protein (p29), which may be regarded as an indicator of hormone-dependent growth, S-phase, G2M-phase, sex, age, histologic grade, and primary tumor extent were all of significant prognostic importance in univariate analyses of patient survival. In the final Cox' model, however, only male sex (P = 0.017), older age, (P < 0.00005) and high grade histologic features (P = 0.006) were associated independently with decreased survival. Among females, decreased expression of c-erbB-2 protein was independently related to decreased patient survival (P = 0.019). In multivariate analysis of time to recurrence, lymph node status (P = 0.0001), epidermal growth factor (EGF) receptor expression (P = 0.013) and estrogen receptor-related protein (P = 0.007) were independent risk indicators, and S-phase fraction (P = 0.074) showed a borderline significance.

CONCLUSION

In this study, sex, age, and histologic grade were independent indicators of deaths from thyroid cancer. Lymph node metastases, EGF-receptor expression, and decreased estrogen receptor-related protein staining persisted as prognostic variables in the final multivariate analysis of recurrence free survival. Alterations in these oncogenes thus seem to play some role in disease progression in papillary thyroid carcinoma, although conventional variables are still important as prognostic indicators.

An immunohistochemical study of p53 protein in the different histological subtypes of gastric carcinoma

p53 mutations are known to occur frequently in human cancers, including gastric carcinomas. Previous studies of its incidence in gastric carcinomas had shown a varying incidence ranging from a low of 4% to as high as 57%. In this study, 42 cases of gastric carcinomas were analyzed for p53 using a commercially available mouse monoclonal antibody in routinely formalin-fixed paraffin-embedded tissue sections. These included 22 intestinal-type (7 well/moderately differentiated and 15 poorly differentiated), 16 diffuse-type and 4 mixed. Altogether, 60% of our cases stained positively for p53. Overall, well/moderately differentiated intestinal-type carcinomas stained more frequently for p53 than poorly differentiated intestinal-type carcinomas (p < 0.075). A comparison between the incidence in diffuse-type (69%) and intestinal type (55%) was unremarkable. p53 staining was also present in 3 of the 4 early cases studied. The results suggest that p53 mutations play an important role in carcinogenesis in gastric carcinoma and further implies that p53 mutation may be an early occurrence during tumor transformation.