Prognostic Implications of DNA Repair, Ploidy and Telomerase in the Malignant Transformation Risk Assessment of Leukoplakia.

BACKGROUND: Although leukoplakia shows a higher risk for malignant transformation to oral cancer, currently there are no clinically relevant biomarker which can predict the potentially high risk leukoplakia. This study aimed to investigate the genetic alterations such as DNA ploidy, telomerase expression and DNA repair capacity as predictive markers of malignant transformation risk of leukoplakia. METHODS: The study was initiated in September 2005 and patients were followed up to March 2014. Two hundred patients with oral leukoplakia, 100 patients with oral cancer and 100 healthy, age and sex matched adults with normal oral mucosa as controls were recruited. The DNA ploidy content was measured by high resolution flow cytometry, level of telomerase expression was identified by TRAP assay and intrinsic DNA repair capacity was measured by mutagen induced chromosome sensitivity assay of cultured peripheral blood lymphocytes. The Chi-square test or Fisher's Exact test was used for comparison of categorical variables between biomarkers. A p value less than or equal to 0.05 was considered as statistically significant. Analysis was performed with SPSS software version 16. Logistic regression was used to find the association between the dependent and three independent variables. RESULTS: There was significant difference in the distribution of ploidy status, telomerase activity and DNA repair capacity among control, leukoplakia and oral cancer group (p<0.001). When the molecular markers were compared with histological grading of leukoplakia, both DNA ploidy analysis and telomerase activity showed statistical significance (p<0.001). Both aneuploidy and telomerase positivity was found to coincide with high-risk sites of leukoplakia and were statistically significant (p.

Assessment of COX-2 expression presence and severity by immunohistochemical method in patients with chronic active gastritis and intestinal metaplasia.

BACKGROUND/AIMS: The risk of gastric cancer is increased in patients with intestinal metaplasia. Cyclooxygenase-2 activity is crucial for gastric cancer cell survival and proliferation. We aimed to assess cyclooxygenase-2 expression in patients with intestinal metaplasia or chronic active gastritis and in patients with or without a family history of gastric cancer, i.e. a first-degree relative with gastric cancer. MATERIALS AND METHODS: One hundred and six patients with histologically proven intestinal metaplasia, chronic active gastritis or normal gastric mucosa were included. Immunohistochemical staining was performed using the immunoperoxidase method. RESULTS: Cyclooxygenase-2 expression was detected in 23.1% of normal gastric mucosa, 70.6% of chronic active gastritis, and 90.5% of intestinal metaplasia patients. Cyclooxygenase-2 expression was significantly higher in intestinal metaplasia than in chronic active gastritis (p=0.018). Cyclooxygenase-2 expression was significantly more severe in the intestinal metaplasia group when compared to the chronic active gastritis group (p=0.017). Severe cyclooxygenase-2 expression (>60% of cells) was more frequent in the intestinal metaplasia group. Cyclooxygenase-2 expression was higher in the Helicobacter pylori-positive group when compared to the Helicobacter pylori-negative group (80.3% vs 57.1%, respectively; p=0.012). Cyclooxygenase-2 expression did not significantly differ according to presence of a first-degree relative with gastric cancer. CONCLUSIONS: Patients with intestinal metaplasia demonstrated increased presence and severity of cyclooxygenase-2 expression. Our findings suggest that cyclooxygenase-2 plays an important role in the stepwise process that eventually leads to gastric cancer. There was no statistically significant difference between the patients with and without a first-degree relative with a history of gastric cancer in terms of cyclooxygenase-2 expression.

Urinary metalloproteinases: noninvasive biomarkers for breast cancer risk assessment.

Matrix metalloproteinases (MMP) and a disintegrin and metalloprotease 12 (ADAM 12) can be detected in the urine of breast cancer patients and provide independent prediction of disease status. To evaluate the potential of urinary metalloproteinases as biomarkers to predict breast cancer risk status, urine samples from women with known risk marker lesions, atypical hyperplasia and lobular carcinoma in situ (LCIS), were analyzed. Urine samples were obtained from 148 women: 44 women with atypical hyperplasia, 24 women with LCIS, and 80 healthy controls. MMP analysis was done using gelatin zymography and ADAM 12 analysis was done via immunoblotting with monospecific antibodies and subsequent densitometric measurement. Positive urinary MMP-9 levels indicated a 5-fold risk of atypical hyperplasia and >13-fold risk of LCIS compared with normal controls. Urinary ADAM 12 levels were significantly elevated in women with atypical hyperplasia and LCIS from normal controls, with receiver operating characteristic curve analysis showing an area under the curve of 0.914 and 0.950, respectively. To assess clinical applicability, a predictive index was developed using ADAM 12 in conjunction with Gail risk scores for women with atypia. Scores above 2.8 on this ADAM 12-Gail risk prediction index score are predictive of atypical hyperplasia (sensitivity, 0.976; specificity, 0.977). Our data suggest that the noninvasive detection and analysis of urinary ADAM 12 and MMP-9 provide important clinical information for use as biomarkers in the identification of women at increased risk of developing breast cancer.

Marriage of a medium-term liver model to surrogate markers--a practical approach for risk and benefit assessment.

The need for a reliable medium-term alternative to traditional long-term rodent test protocols for carcinogen risk assessment is pressing given the immense variety of compounds being developed for introduction into the human environment. The established lack of a complete correlation between mutagenicity and carcinogenicity means that recourse must be made to an in vivo model. Optimally, this model should be able to detect not only complete carcinogenic or promoting potential but also any ability to inhibit neoplasia. In order to be effective, it must take into account the available detailed knowledge on mechanisms of action of carcinogens and modulating agents. The Ito model, for which a uniquely comprehensive set of background data has already been accumulated, has a solid scientific basis; this model utilizes quantitative data for glutathione S transferase-positive foci as the preneoplasia-based surrogate end point (PSE). A very practical candidate for routine application, its predictive power, its flexibility, and its capacity to incorporate a range of mechanism-based surrogate end points (MSEs) provide a powerful tool for attainment of the twin goals of detecting carcinogenic agents and identifying promising chemopreventors.