Absence of lymphangiogenesis in ductal breast cancer at the primary tumor site.

Solid evidence for a relationship between lymphangiogenesis and prognosis in human breast cancer is still lacking. Evidence for ongoing lymphangiogenesis in breast cancer is only provided by animal studies. In the present study we investigated lymphatic vessel density as well as the expression level of the lymphangiogenic factors VEGF-C and -D in a series of 121 ductal breast cancer tissues using immunohistochemical stainings. We found that in the primary tumors the lymphatic vessel density, as well as the expression of both VEGF-C and -D, did not relate to grade, tumor stage, progression or patient survival. Furthermore, in tumors in which lymphatic vessels were present, a Ki-67/podoplanin double staining indicated the absence of proliferating lymphatic endothelial cells. In contrast, we did find a correlation between intratumoral lymphatic vessel density inside the lymph node metastases and patient survival. Another parameter that revealed prognostic value was the presence of tumor cells within the lymphatic vessels. This parameter did predict survival in patients with an age below 63 only. Interestingly, expression of VEGF-D was found to be related to the presence of intralymphatic tumor cells.

Loss of continuity in the thin epicardial layer because of endomysial fibrosis increases the complexity of atrial fibrillatory conduction.

BACKGROUND: The transition from persistent to permanent atrial fibrillation (AF) is associated with increased complexity of fibrillatory conduction. We have investigated the spatial distribution of fibrillation waves and structural alterations in the atrial free walls in a goat model of AF. METHODS AND RESULTS: AF was maintained for 3 weeks (short term [ST], persistent AF) or 6 months (long term [LT], permanent AF). Fibrillation patterns were assessed with epicardial mapping. The origin of fibrillation waves and sites of conduction abnormalities were more homogeneously distributed in LT than in ST goats. Histologically, the total area fraction occupied by fibrous tissue and the degree of perimysial fibrosis (separation between myocyte bundles) were not significantly different between groups. However, endomysial fibrosis (distance between myocytes within bundles) was significantly larger in LT goats, particularly in the outer millimeter of the atria. By contrast, myocyte diameters were larger in LT goats throughout the atrial walls. High-resolution optical mapping showed that epicardial wavefront expansion was slower and more anisotropic in LT than in ST goats. Finally, a mathematical model of a simplified atrial architecture confirmed the potential impact of epicardial endomysial fibrosis on AF complexity. CONCLUSIONS: Altered propagation after 6 months of AF is consistent with homogeneous structural remodeling in the outer millimeter of the atria. Loss of continuity of the epicardial layer because of endomysial fibrosis may reduce its synchronizing effect, thereby increasing the complexity of fibrillatory conduction pathways. The exact distribution of fibrosis may be more important for the occurrence of conduction disturbances than the overall quantity.

Early life exposure to famine and colorectal cancer risk: a role for epigenetic mechanisms.

BACKGROUND: Exposure to energy restriction during childhood and adolescence is associated with a lower risk of developing colorectal cancer (CRC). Epigenetic dysregulation during this critical period of growth and development may be a mechanism to explain such observations. Within the Netherlands Cohort Study on diet and cancer, we investigated the association between early life energy restriction and risk of subsequent CRC characterized by the (promoter) CpG island methylation phenotype (CIMP). METHODOLOGY/PRINCIPAL FINDINGS: Information on diet and risk factors was collected by baseline questionnaire (n = 120,856). Three indicators of exposure were assessed: place of residence during the Hunger Winter (1944-45) and World War II years (1940-44), and father's employment status during the Economic Depression (1932-40). Methylation specific PCR (MSP) on DNA from paraffin embedded tumor tissue was performed to determine CIMP status according to the Weisenberger markers. After 7.3 years of follow-up, 603 cases and 4631 sub-cohort members were available for analysis. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals for CIMP+ (27.7%) and CIMP- (72.3%) tumors according to the three time periods of energy restriction, adjusted for age and gender. Individuals exposed to severe famine during the Hunger Winter had a decreased risk of developing a tumor characterized by CIMP compared to those not exposed (HR 0.65, 95%CI: 0.45-0.92). Further categorizing individuals by an index of '0-1' '2-3' or '4-7' genes methylated in the promoter region suggested that exposure to the Hunger Winter was associated with the degree of promoter hypermethylation ('0-1 genes methylated' HR = 1.01, 95%CI:0.74-1.37; '2-3 genes methylated' HR = 0.83, 95% CI:0.61-1.15; '4-7 genes methylated' HR = 0.72, 95% CI:0.49-1.04). No associations were observed with respect to the Economic Depression and WWII years. CONCLUSIONS: This is the first study indicating that exposure to a severe, transient environmental condition during adolescence and young adulthood may result in persistent epigenetic changes that later influence CRC development.

The galectin profile of the endothelium: altered expression and localization in activated and tumor endothelial cells.

We previously identified overexpression of galectin-1 in activated tumor endothelium. Currently, the tumor vasculature is a target for therapeutic approaches. Little is known about galectin expression and regulation in the tumor vasculature. Here, we report the expression of galectin-1/-3/-8/-9 in the endothelium as determined by quantitative PCR, Western blot, flow cytometry, and immunohistochemistry. Galectin-2/-4/-12 were detectable at the mRNA level, albeit very low. Galectin-8 and -9 displayed alternative splicing. Immunohistochemistry of normal tissues revealed a broad but low expression of galectin-1 in the vasculature, whereas the expression levels and localization of the other galectins varied. Endothelial cell activation in vitro significantly increased the expression of galectin-1 (5.32 +/- 1.97; P = 0.04) and decreased the expression of both galectin-8 (0.59 +/- 0.12; P < 0.04) and galectin-9 (0.32 +/- 0.06; P < 0.002). Galectin-3 expression was unaltered. Although a portion of these proteins is expressed intracellularly, the membrane protein level of galectin-1/-8/-9 was significantly increased on cell activation in vitro, 6-fold (P = 0.005), 3-fold (P = 0.002), and 1.4-fold (P = 0.04), respectively. Altered expression levels and cellular localization was also observed in vivo in the endothelium of human tumor tissue compared with normal tissue. These data show that endothelial cells express several members of the galectin family and that their expression and distribution changes on cell activation, resulting in a different profile in the tumor vasculature. This offers opportunities to develop therapeutic strategies that are independent of tumor type.