In vivo albumin labeling and lymphatic imaging.

The ability to accurately and easily locate sentinel lymph nodes (LNs) with noninvasive imaging methods would assist in tumor staging and patient management. For this purpose, we developed a lymphatic imaging agent by mixing fluorine-18 aluminum fluoride-labeled NOTA (1,4,7-triazacyclononane-N,N',N''-triacetic acid)-conjugated truncated Evans blue ((18)F-AlF-NEB) and Evans blue (EB) dye. After local injection, both (18)F-AlF-NEB and EB form complexes with endogenous albumin in the interstitial fluid and allow for visualizing the lymphatic system. Positron emission tomography (PET) and/or optical imaging of LNs was performed in three different animal models including a hind limb inflammation model, an orthotropic breast cancer model, and a metastatic breast cancer model. In all three models, the LNs can be distinguished clearly by the apparent blue color and strong fluorescence signal from EB as well as a high-intensity PET signal from (18)F-AlF-NEB. The lymphatic vessels between the LNs can also be optically visualized. The easy preparation, excellent PET and optical imaging quality, and biosafety suggest that this combination of (18)F-AlF-NEB and EB has great potential for clinical application to map sentinel LNs and provide intraoperative guidance.

MTHFR genotype and colorectal adenoma recurrence: data from a double-blind placebo-controlled clinical trial.

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in folate metabolism. We assessed the association between two common MTHFR variants, 677C>T and 1298A>C, and adenoma recurrence in the context of a randomized double- blind clinical trial of aspirin use and folate supplementation. We used generalized linear regression to estimate risk ratios and 95% confidence intervals (95% CI) for recurrence, adjusting for age, sex, clinical center, follow-up time, and treatment status. Neither MTHFR polymorphism was associated with overall or advanced adenoma recurrence. Compared with those with two wild-type alleles, the relative risk for advanced adenoma was 0.75 (95% CI, 0.36-1.55) for the MTHFR 677 TT genotype and 1.16 (95% CI, 0.58-2.33) for the MTHFR 1298 CC genotype. The effect of folate supplementation on recurrence risk did not differ by genotype. Our findings indicate that the MTHFR genotype does not change adenoma risk in a manner similar to its effect on colorectal cancer, and does not modify the effect of folate supplementation on metachronous adenoma risk.

Serum proteomic profiles suggest celecoxib-modulated targets and response predictors.

Cyclooxygenase-2 is a valid target for cancer prevention and treatment. This has been shown in preclinical and clinical cancer prevention studies by using a cyclooxygenase-2 inhibitor, celecoxib. When used in a randomized cancer prevention clinical trial on patients with the inherited autosomal dominant condition, familial adenomatous polyposis, celecoxib proved efficacious. However, a remarkable heterogeneity in patients' responses to the chemopreventive effects of celecoxib was observed. Proteomic profiling of sera from these patients identified several markers, the expression of which was specifically modulated after treatment with celecoxib. A decision tree algorithm identified classifiers for response to celecoxib with relatively high sensitivity but moderate to low specificity. In particular, a spectral feature at m/z 16,961.4 was identified as a strong discriminator between response and nonresponse to celecoxib at the highest dose.

Cyclooxygenase-2 polymorphisms, aspirin treatment, and risk for colorectal adenoma recurrence--data from a randomized clinical trial.

Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step in the production of prostaglandins, potent mediators of inflammation. Chronic inflammation plays an important role in the development and progression of colorectal cancer. Aspirin inhibits COX-2 activity and lowers the risk for colorectal adenomas and cancer. We investigated whether common genetic variation in COX-2 influenced risk for colorectal adenoma recurrence among 979 participants in the Aspirin/Folate Polyp Prevention Study who were randomly assigned to placebo or aspirin and followed for 3 years for the occurrence of new adenomas. Of these participants, 44.2% developed at least one new adenoma during follow-up. Adjusted relative risks and 95% confidence intervals (95% CI) were calculated to test the association between genetic variation at six COX-2 single-nucleotide polymorphisms and adenoma occurrence and interaction with aspirin treatment. Two single-nucleotide polymorphisms were significantly associated with increased adenoma recurrence: for rs5277, homozygous carriers of the minor C allele had a 51% increased risk compared with GG homozygotes (relative risk, 1.51; 95% CI, 1.01-2.25), and for rs4648310, heterozygous carriers of the minor G allele had a 37% increased risk compared with AA homozygotes (relative risk, 1.37; 95% CI, 1.05-1.79). (There were no minor allele homozygotes.) In stratified analyses, there was suggestive evidence that rs4648319 modified the effect of aspirin. These results support the hypothesis that COX-2 plays a role in the etiology of colon cancer and may be a target for aspirin chemoprevention and warrant further investigation in other colorectal adenoma and cancer populations.

Molecular profiling of angiogenesis markers.

The goal of this study was to develop a sensitive, simple, and widely applicable assay to measure copy numbers of specific mRNAs using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), and identify a profile of gene expression closely associated with angiogenesis. We measured a panel of nine potential angiogenesis markers from a mouse transgenic model of prostate adenocarcinoma (TRAMP) and a mouse skin model of vascular endothelial growth factor (VEGF)-driven angiogenesis. In both models, expression of VEGF correlated with expression of mRNAs encoding other angiogenic cytokines (angiopoietin-1 and angiopoietin-2), endothelial cell receptor tyrosine kinases (Flt-1, KDR, Tie-1), and endothelial cell adhesion molecules (VE-cadherin, PECAM-1). Relative to control, in dermis highly stimulated by VEGF, the Ang-2 mRNA transcript numbers increased 35-fold, PECAM-1 and VE-cadherin increased 10-fold, Tie-1 increased 8-fold, KDR and Flt-1 each increased 4-fold, and Ang-1 increased 2-fold. All transcript numbers were correspondingly reduced in skin with less VEGF expression, indicating a relationship of each of these seven markers with VEGF. Thus, this study identifies a highly efficient method for precise quantification of a panel of seven specific mRNAs that correlate with VEGF expression and VEGF-induced neovascularization, and it provides evidence that real-time quantitative RT-PCR offers a highly sensitive strategy for monitoring angiogenesis.