BACKGROUND: The Toll-like receptor (TLR) 4 signalling pathway has been shown to have oncogenic effects in vitro and in vivo. To demonstrate the role of TLR4 signalling in colon tumourigenesis, we examined the expression of TLR4 and myeloid differentiation factor 88 (MyD88) in colorectal cancer (CRC). METHODS: The expression of TLR4 and MyD88 in 108 CRC samples, 15 adenomas, and 15 normal mucosae was evaluated by immunohistochemistry, and the correlations between their immunoscores and clinicopathological variables, including disease-free survival (DFS) and overall survival (OS), were analysed. RESULTS: Compared with normal mucosae and adenomas, 20% cancers displayed high expression of TLR4, and 23% cancers showed high expression of MyD88. The high expression of TLR4 and MyD88 was significantly correlated with liver metastasis (P ¼ 0.0001, P ¼ 0.0054). In univariate analysis, the high expression of TLR4 was significantly associated with shorter OS (hazard ratio (HR): 2.17; 95% confidence interval (95% CI): 1.15 -4.07; P ¼ 0.015). The high expression of MyD88 expression was significantly associated with poor DFS and OS (HR: 2.33; 95% CI: 1.31 -4.13; P ¼ 0.0038 and HR: 3.03; 95% CI: 1.67 -5.48; P ¼ 0.0002). The high combined expression of TLR4 and MyD88 was also significantly associated with poor DFS and OS (HR: 2.25; 95% CI: 1.27 -3.99; P ¼ 0.0053 and HR: 2.97; 95% CI: 1.64 -5.38; P ¼ 0.0003). Multivariate analysis showed that high expressions of TLR4 (OS: adjusted HR: 1.88; 95% CI: 0.99 -3.55; P ¼ 0.0298) and MyD88 (DFS: adjusted HR: 1.93; 95% CI: 1.01 -3.67; P ¼ 0.0441; OS: adjusted HR: 2.25; 95% CI: 1.17 -4.33; P ¼ 0.0112) were independent prognostic factors of OS. Furthermore, high co-expression of TLR4/MyD88 was strongly associated with both poor DFS and OS. CONCLUSION: Our findings suggest that high expression of TLR4 and MyD88 is associated with liver metastasis and is an independent predictor of poor prognosis in patients with CRC.

Pituitary adenomas producing almost exclusively growth hormones (GH) have been ultrastructurally classified into two distinct types: densely granulated somatotroph (DG) adenomas and sparsely granulated (SG) adenomas. Fibrous body (FB), an intracytoplasmic globular aggregation of cytokeratin (CK) filaments, is a hallmark of SG adenomas. Under light microscope, FB could be identified by CK immunohistochemistry as a dot-pattern immunoreaction versus a perinuclear pattern for cells without FB. However, it has been noted that numerous adenomas contain mixed populations of the two patterns. To clarify clinicopathological characteristics of the adenomas with mixed populations ("intermediate type" adenomas) and to confirm clinicopathological differences between strictly defined DG-type and SG-type adenomas, we performed this study on 104 GH cell adenomas. Having segregated "intermediate-type" adenomas (26 cases), we found significant differences between typical DG-type (47 cases) and SG-type adenomas (31 cases); SG-type adenomas had younger ages (44 vs. 50), higher frequency of macroadenomas (86% vs. 58%), invasiveness (65% vs. 38%), advanced grades (3 or 4) in Knosp's classification (50% vs. 24%), and weaker immunoreaction for GH, beta-TSH, alpha-subunit, E-cadherin, and beta-catenin. Clinicopathological characteristics of "intermediate-type" adenomas were identical to those of DG-type adenomas. These findings confirm that SG-type adenoma is a distinct section of GH cell adenomas with special properties and biological behavior, and suggest that intermediate-phenotype adenomas are enrolled in DG-type adenomas. Special properties and biological behavior of SG-type adenomas may appear after the majority of tumor cells possess a fully developed fibrous body.

High-mobility group A2 is highly expressed during embryogenesis and in various benign and malignant tumors. Recent studies report that high-mobility group A2 is negatively regulated by the let-7 microRNAs (miRNAs) family in vitro. The development of pituitary adenomas in high-mobility group A2 transgenic mice showed that high-mobility group A2 may be involved in pituitary tumorigenesis. However, no studies have investigated the clinical significance of high-mobility group A2 and its relationship to the let-7 miRNA family in human pituitary adenomas. Using immunohistochemistry, we analyzed high-mobility group A2 expression with respect to various clinicopathologic factors in 98 pituitary adenomas. Overexpression of high-mobility group A2 was observed in 39% (38/98) of pituitary adenomas compared with normal adenohypophysial tissue and was frequently found in adenomas including prolactin (PRL), adrenocorticotrophic hormone, or follicle-stimulating hormone/luteinizing hormone and in null cell adenomas, but relatively rare in growth hormone (GH) and mixed GH/PRL adenomas. High-mobility group A2 expression was significantly associated with tumor invasion (Po0.05) and was significantly higher in grade IV than in grades I, II, and III adenomas (Po0.05). High levels of high-mobility group A2 expression were more frequently observed in macroadenomas than in microadenomas (Po0.05). High levels of high-mobility group A2 expression also significantly correlated with the proliferation marker Ki-67 (Po0.0001). Real-time quantitative RT-PCR analysis was carried out to evaluate the expression of let-7 in 55 pituitary adenomas. Subsequently, decreased expression of let-7 was confirmed in 23 of 55 (42%) adenomas and was correlated with high-grade tumors (Po0.05). An inverse correlation between let-7 and highmobility group A2 expression was evident (R ¼ À0.33, Po0.05). These findings support a causal link between let-7 and high-mobility group A2 whereby loss of let-7 expression induces high-mobility group A2 upregulation that represents an important mechanism in pituitary tumorigenesis and progression.

To study the paracrine effect of IL-10 on autoimmune insulitis and diabetes, we produced IL-10 transgenic non-obese diabetic (NOD) mice (NOD-IL-10) in which murine IL-10 was expressed in pancreatic islet A cells under the control of a rat glucagon promoter without directly manipulating pancreatic islet B cells. Among 11 founder mice, four of four males and three of seven females developed diabetes by 10 weeks of age. Histological analysis of six NOD-IL-10 revealed severe insulitis and prominent ductal proliferation. NOD-IL-10 also showed spotty lymphocytic infiltration in the lung and liver in four of six founder mice. The onset of diabetes in NOD-IL-10 was remarkably earlier than that of 14 weeks of age at the earliest in female non-transgenic NOD mice. When the NOD-IL-10 mouse was backcrossed to C57BL/6 mice, none of the resulting F1, B-N2 or B-N3 generation toward C57BL/6 mice showed diabetes even at 39 weeks of age, in spite of the presence of peri-insulitis and prominent ductal proliferation, while two of four mice of the N-N2 generation toward NOD mice showed early-onset diabetes. Thus, transgenic paracrine expression of IL-10 in situ in the NOD genetic background enhances autoimmune insulitis and diabetes in their onset and severity, ignoring gender difference. Because expression of IL-10 was detected by polymerase chain reaction in pancreatic islets of non-transgenic NOD mice after 5 weeks of age, IL-10 secreted in situ is regarded to enhance cell-mediated autoimmune diabetes, in spite of established in vitro anti-Th1 activity of IL-10.