Expression of Pref-1 and Related Chemokines during theDevelopment of Rat Mesenteric Lymph Nodes.

OBJECTIVE: The aim of this study was to investigate the ability of Pref-1+ adipocyte progenitor cells to mobilize into mesenteric lymph nodes (MLNs) and the dynamic expression of related chemokines during the development of rat MLNs. METHODS: Immunohistochemical analyses were used to detect the expression of Pref-1 and related chemokines. Transmission electron microscopy (TEM) was used to observe the changes in ultrastructure of MLNs. RESULTS: Cells containing lipid droplets were found in all rat MLNs at embryonic day (E) 18.5, 2 and 6 weeks (w) after birth, and they were similar to fibroblastic reticular cells (FRCs) or follicular dendritic cells (FDCs) under TEM. Pref-1+ adipocyte progenitor cells were found in all MLNs. The expression level of Pref-1 was significantly increased at 2 w after birth and decreased at 6 w after birth. The tendency of Cxcl12 expression was consistent with that of Pref-1 and was positively correlated with the expression of Pref-1 (P < 0.01; r = 0.897). At E18.5, Cxcl13, and Ccr7 were significantly expressed in the MLN anlage, but the expression level of Ccl21 was low. The expression level of Cxcl13, Ccr7, and Ccl21 in MLN were significantly increased at 2 w after birth (P < 0.05), while the expression of Ccr7 and Ccl21 were significantly decreased at 6 w after birth (P < 0.05). CONCLUSION: Adipocyte progenitor cells are involved in the rat MLNs development through differentiation into FRC and FDC. The expression of the relevant chemokines during the development of MLNs is dynamic and may be related to the maintenance of lymph nodes self-balance state.

Heparanase expression, degradation of basement membrane and low degree of infiltration by immunocytes correlate with invasion and progression of human gastric cancer.

AIM: To disclose the mechanisms that accelerate or limit tumor invasion and metastasis in gastric cancer patients. METHODS: The heparanase expression, continuity of basement, degree of infiltration by dendritic cells and lymphocytes in gastric cancer tissues from 33 the early and late stage patients were examined by immunohistochemistry, in situ hybridization and transmission electron microscopy. RESULTS: Heparanase mRNA expression in the late stage patients with gastric cancer was stronger than that in the early stage gastric cancer patients. In the early stage gastric cancer tissues, basement membrane (BM) appeared intact, whereas in the late stage, discontinuous BM was often present. The density of S100 protein positive tumor infiltrating dendritic cells (TIDC) in the early stage gastric cancer tissues was higher than that in the late stage. The infiltrating degree of tumor infiltrating lymphocytes (TIL) in the early stage patients whose tumor tissues contained a high density of TIDC was significantly higher than that in the late stage gastric cancer tissues patients with a low density of TIDC. There were few cancer cells penetrated through the continuous BM of cancer nests in the early stage gastric cancers, but many cancer cells were found outside of the defective BM of cancer nests in the late stage. CONCLUSION: Our results suggest that strong heparanase expression is related with the degradation of BM which allows or accelerates tumor invasion and metastasis. However, high density of TIDC and degree of infiltration by TIL are associated with tumor progression in human gastric cancers.

Morphological observation of tumor infiltrating immunocytes in human rectal cancer.

AIM: To investigate the morphological characterization of tumor infiltrating dendritic cells (TIDCs) and tumor infiltrating lymphocytes (TILs) in human rectal cancer. METHODS: Light and electron microscopy as well as immunohistochemistry were used to observe the distributive and morphological changes of TIDCs and TILs. RESULTS: TIDCs were mainly located in tumor-surrounding tissue. The number of TIDCs in the earlier stage was higher than that in the later stage (P<0.01). TILs were mainly seen in adjacent tissue of cancers and tumor-surrounding tissue. There were more TILs in the earlier stage than that in the later stage (P<0.01). Under electron microscope, TIDCs were irregular in shape and exhibited many dendritic protrusions. It is not obvious that cancer cells perforated the basement membrane and TILs were arranged along the basement membrane in the earlier stage. In the later stage, it is explicit that cancer cells perforated the basement membrane and surrounded by TILs. There were contacts among TIDCs, TILs and tumor cell. One TIDCs contacted one or several TILs which clustered around TIDCs. Glycogen granules were seen between TIDCs and TILs. CONCLUSION: The number of TIDCs and TILs is related with tumor progression There exist close relationships among TIDCs, TILs and tumor cell.