Co-expression of nuclear and cytoplasmic HMGB1 is inversely associated with infiltration of CD45RO+ T cells and prognosis in patients with stage IIIB colon cancer

<p>Abstract</p> <p>Background</p> <p>The intratumoral infiltration of T cells, especially memory T cells, is associated with a favorable prognosis in early colorectal cancers. However, the mechanism underlying this process remains elusive. This study examined whether high-mobility group box 1 (HMGB1), a damage-associated molecular pattern (DAMP) molecule, is involved in the infiltration of T cells and disease progression in locally advanced colon cancer.</p> <p>Methods</p> <p>Seventy-two cases of pathologically-confirmed specimens were obtained from patients with stage IIIB (T3N1M0) colon cancer who underwent radical resection between January 1999 and May 2002 at the Cancer Center of Sun Yat-Sen University. The density of tumor-infiltrating lymphocytes (TILs) within the tumor tissue and the expression of HMGB1 in the cancer cells were examined via immunohistochemical analysis. The phenotype of CD45RO+ cells was confirmed using a flow cytometric assay. The association between HMGB1 expression, the density of TILs, and the 5-year survival rate were analyzed.</p> <p>Results</p> <p>The density of CD45RO+ T cells within the tumor was independently prognostic, although a higher density of CD3+ T cells was also associated with a favorable prognosis. More importantly, the expression of HMGB1 was observed in both the nucleus and the cytoplasm (co-expression pattern) in a subset of colon cancer tissues, whereas nuclear-only expression of HMGB1 (nuclear expression pattern) existed in most of the cancer tissues and normal mucosa. The co-expression pattern of HMGB1 in colon cancer cells was inversely associated with the infiltration of both CD3+ and CD45RO+ T cells and 5-year survival rates.</p> <p>Conclusions</p> <p>This study revealed that the co-expression of HMGB1 is inversely associated with the infiltration of CD45RO+ T cells and prognosis in patients with stage IIIB colon cancer, indicating that the distribution patterns of HMGB1 might contribute to the progression of colon cancer via modulation of the local immune response.</p

Unoccupied electronic states in CaB6 studied by density functional theory and EELS measurements

The electronic structure of CaB6 has recently attracted great interest because of the discovery that this compound is unexpectedly ferromagnetic and exhibits a surprisingly large thermoelectric effect. We have concentrated on studying the unoccupied electronic states by investigating the boron 1s core-level spectroscopy. Comparison of our data from electron energy-loss spectroscopy with that from x-ray absorption spectroscopy using the total electron yield mode reveals evidence for sample inhomogeneity. The ab initio band structural method has been successfully applied to simulate the overall features found in the boron 1s absorption spectrum. Correlation with the results of a ground state energy-band calculation allows the interpretation of the spectral features in terms of the density of states of the unoccupied conduction band, in particular the identification of a feature associated with hybridization of Ca d orbitals with B p orbitals. This interpretation is confirmed by comparison with similar calculations for related boride systems. However, simulation spectral data cannot be reconciled with high-resolution experimental data at the absorption threshold. The possibility of either the failure of the theoretical method employed to account for many-body effects and/or the need for improved experimental measurements is discussed