Sensitivity and specificity of the empirical lymphocyte genome sensitivity (LGS) assay: implications for improving cancer diagnostics.

Lymphocyte responses from 208 individuals: 20 with melanoma, 34 with colon cancer, and 4 with lung cancer (58), 18 with suspected melanoma, 28 with polyposis, and 10 with COPD (56), and 94 healthy volunteers were examined. The natural logarithm of the Olive tail moment (OTM) was plotted for exposure to UVA through 5 different agar depths (100 cell measurements/depth) and analyzed using a repeated measures regression model. Responses of patients with cancer plateaued after treatment with different UVA intensities, but returned toward control values for healthy volunteers. For precancerous conditions and suspected cancers, intermediate responses occurred. ROC analysis of mean log OTMs, for cancers plus precancerous/suspect conditions vs. controls, cancer vs. precancerous/suspect conditions plus controls, and cancer vs. controls, gave areas under the curve of 0.87, 0.89, and 0.93, respectively (P<0.001). Optimization allowed test sensitivity or specificity to approach 100% with acceptable complementary measures. This modified comet assay could represent a stand-alone test or an adjunct to other investigative procedures for detecting cancer.

In vitro sensitivities to UVA of lymphocytes from patients with colon and melanoma cancers and precancerous states in the micronucleus and the Comet assays.

To use lymphocytes as surrogate cells to investigate their in vitro sensitivities to ultraviolet (UV) treatment in different cancers and precancerous states by comparison with lymphocytes from healthy control individuals was the main aim of this research. UV light induces precise cellular and genomic mutations. In this study, the effect of ultraviolet A (UVA) (320-400 nm) was used as a generic mutagen to evaluate in vitro different sensitivities from lymphocytes of patients with suspected melanoma (SM), malignant melanoma (MM), polyposis coli (PC) and colorectal cancer (CRC). DNA damage was evaluated by two different methods: the micronucleus (MN) assay and the Comet assay. The baseline frequency of MNs was significantly increased in lymphocytes from all patients (SM, MM, PC and CRC) when compared to healthy individuals. After UV irradiation, MN frequencies were significantly increased in lymphocytes of all groups, both patients and healthy individuals. However, the MN frequency in all patient groups was significantly higher than in the healthy individual group. Similar results for the induction of genomic DNA damage were obtained for the Comet assay. Also for the Comet assay, UVA-induced DNA damage for all four patient groups was significantly increased when compared to healthy individuals (SM, MM, PC and CRC groups: P < 0.001). Conclusively, peripheral lymphocytes from patients with cancers MM and CRC or precancerous states SM and PC are more sensitive to a generic mutagen such as UVA than lymphocytes from healthy individuals. This feature may be used as an essential biomarker to screen and diagnose precancerous states and cancers in early stages.

Flavonoids inhibit the genotoxicity of hydrogen peroxide (H(2)O(2)) and of the food mutagen 2-amino-3-methylimadazo[4,5-f]-quinoline (IQ) in lymphocytes from patients with inflammatory bowel disease (IBD).

Inflammatory bowel disease (IBD) including Crohn's disease (CD) and ulcerative colitis (UC) is a chronic inflammatory gastrointestinal autoimmune condition with an inappropriate immune response. We investigated DNA damage induced in vitro in lymphocytes from IBD patients caused by oxidative stress through H(2)O(2) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and whether the plant flavonoids, quercetin and epicatechin, found in fruits, tea and soybeans could effectively reduce such stress. Lymphocytes from IBD patients and healthy volunteers were treated with 50 microg/ml H(2)O(2) or IQ in the presence of quercetin (0-250 microg/ml) or epicatechin (0-100 microg/ml). Flavonoid supplementation (250 microM quercetin or 100 microM epicatechin) caused an overall significant decrease of induced DNA damage resulting in a 48.6% (P < 0.001) reduction of H(2)O(2)-induced and a 43% (P < 0.001) reduction of IQ-induced DNA damage within the patient groups; for the control groups, reductions in DNA damage were 35.2 and 57.1%, respectively (both, P < 0.001). There was less induced DNA damage within lymphocytes from UC patients compared to CD patients for both series of experiments (H(2)O(2) and quercetin, IQ and epicatechin). In conclusion, flavonoids dramatically reduced oxidative stress in vitro in lymphocytes from IBD patients and healthy individuals. Thus, flavonoids could be very effective in the treatment of oxidative stress and encouraged in the diet of IBD patients.

Chaga mushroom extract inhibits oxidative DNA damage in lymphocytes of patients with inflammatory bowel disease.

Inflammatory Bowel Disease (IBD) is partly caused by oxidative stress from free radicals and reduced antioxidant levels. Using hydrogen peroxide to induce oxidative stress in vitro in peripheral lymphocytes we investigated the induction of DNA damage supplemented with ethanolic extract of Chaga mushroom as a protective antioxidant. Lymphocytes were obtained from 20 IBD patients and 20 healthy volunteers. For treatment, a constant H_{2}O_{2 } dose (50 microg/ml) was used with variable doses of Chaga extract (10-500 microg/ml). DNA damage was evaluated in 50 cells per individual and dose using the Comet assay (making 1000 observations per experimental point ensuring appropriate statistical power). Chaga supplementation resulted in a 54.9% (p < 0.001) reduction of H_{2}O_{2 } induced DNA damage within the patient group and 34.9% (p < 0.001) within the control group. Lymphocytes from Crohn's disease (CD) patients had a greater basic DNA damage than Ulcerative Colitis (UC) patients (p < 0.001). Conclusively, Chaga extract reduces oxidative stress in lymphocytes from IBD patients and also healthy individuals when challenged in vitro. Thus, Chaga extract could be a possible and valuable supplement to inhibit oxidative stress in general.

Ethnicity, gender, and socioeconomic status as risk factors for esophagitis and Barrett's esophagus.

Barrett's esophagus is thought to be a disease occurring predominantly in White Caucasian males of higher socioeconomic status. There are no published studies simultaneously examining risk of Barrett's esophagus according to ethnicity, gender, and socioeconomic status within a single data set. The authors conducted a retrospective case-control analysis within a cross-sectional study to determine risk of Barrett's esophagus in relation to sociodemographic variables in a large United Kingdom population. All patients undergoing upper gastrointestinal endoscopy at two clinical centers between January 2000 and January 2003 were evaluated. Data on ethnicity, age, gender, socioeconomic status, and the presence of Barrett's esophagus and esophagitis at endoscopy were collected. A total of 20,310 patients were analyzed. Barrett's esophagus was more common in White Caucasians (401/14,095 (2.8%)) than in South Asians (16/5,190 (0.3%)) (adjusted odds ratio (OR)=6.03, 95% confidence interval (CI): 3.56, 10.22), as was esophagitis (2,500/14,095 (17.7%) vs. 557/5,190 (10.7%); adjusted OR=1.76, 95% CI: 1.57, 1.97). Patients with Barrett's esophagus were also more likely to be male (adjusted OR=2.70, 95% CI: 2.18, 3.35) and of higher socioeconomic status (adjusted OR=1.58, 95% CI: 1.16, 2.15 (top tertile vs. bottom tertile)). White Caucasian ethnicity, male gender, and higher socioeconomic status are independent risk factors for Barrett's esophagus.