Brain-specific Angiogenesis Inhibitor 1 Expression Research Articles

The regulation of BAI1 in astrocytes through the STAT3/EZH2 axis relieves neuronal apoptosis in rats with Alzheimer’s disease

Alzheimer’s disease (AD) is a common neurodegenerative disease. Previous studies have identified the critical role of astrocytes in the progression of AD. The focus of this study revolves around clarifying the regulatory mechanism of the STAT3/EZH2/BAI1 axis in astrocytes in AD. We successfully developed a rat model of AD, and measured the learning and cognitive ability of the rats by Morris water maze experiment. HE and Nissl’s staining were used for histomorphological identification of the rat hippocampus. Meanwhile, immunofluorescence and immunohistochemistry were used to detect astrocyte activation and brain-specific angiogenesis inhibitor-1 (BAI1) expression in rat hippocampal tissue, respectively. The role of STAT3/EZH2/BAI1 regulating axis in astrocyte activation and neuronal cell apoptosis was verified by establishing the co-culture system of astrocytes and neuronal cells in vitro. Western Blot (WB) was used to detect the expression of associated proteins, and enzyme-linked immunosorbent assay (ELISA) was used to detect astrocyte neurotrophic factor secretion. Hochest/PI staining and flow cytometry were used to observe neuronal apoptosis. Compared with the sham group, AD rats showed significantly decreased cognitive and learning abilities, noticeable hippocampal tissue damage, and significantly low levels of BAI1 expression. In in vitro models, BAI1 was found to inhibit astrocyte activation and enhance the secretion of neurotrophins, resulting in decrease of neurone apoptosis. The regulation of BAI1 by the STAT3/EZH2 axis was shown to affect astrocyte activation and neuronal cell apoptosis. In conclusion, this study represents the pioneering discovery that regulated by the STAT3/EZH2 axis, BAI1 suppresses astrocyte activation, thus reducing neuronal apoptosis.

BAI1 nuclear expression reflects the survival of nonsmoking non-small cell lung cancer patients.

BackgroundSmoking‐ and nonsmoking‐associated lung cancers have different mechanisms of carcinogenesis. We divided non‐small cell lung cancer (NSCLC) patients into nonsmoking and smoking groups with the aim of trying to understand the utility of brain‐specific angiogenesis inhibitor 1 (BAI1) expression in the separate groups.MethodsClinicopathological data were obtained from 148 patients who had undergone surgery for NSCLC of the lung. Tissue microarray blocks were made of samples from NSCLC patients. Two pathologists graded the intensity of BAI1 expression as high or low expression in the cancer cells of patients in the smoking and nonsmoking groups.ResultsNSCLC nonsmokers with higher BAI1 nuclear expression had poor disease‐specific survival (DSS) (hazard ratio: 2.679; 95% confidence interval [CI]:1.022–7.022, p = 0.045). The Kaplan–Meier survival curve confirmed that higher BAI1 expression was significantly associated with poor DSS (p = 0.034) in the nonsmoking group.ConclusionsWe divided NSCLC patients into nonsmoking and smoking groups and found that nuclear BAI1 expression was related to patient survival in nonsmoking NSCLC patients. We suggest BAI1 expression as a predictive marker of nonsmoking‐associated NSCLC and recommend that it be evaluated as an AJCC staging criterion in the future.

LncRNA embryonic stem cells expressed 1 (Lncenc1) is identified as a novel regulator in neuropathic pain by interacting with EZH2 and downregulating the expression of Bai1 in mouse microglia

LncRNA embryonic stem cells expressed 1 (Lncenc1), named after its high expression in naïve embryonic stem cells (nESCs), has been rarely studied in almost all pathological processes. Evidences suggest that Lncenc1 is likely to work in the form of RNA-protein complex. Here, we found that Lncenc1 in dorsal root ganglion (DRG) was significantly upregulated in response to mouse nerve injury caused by partial sciatic nerve ligation (pSNL). Overexpression of Lncenc1 mediated by adenoviral expression vector promoted the activation of microglia and the production of inflammatory cytokines including TNF-α, IL-1β and MCP-1. In contrast, knockdown of Lncenc1 suppressed activation of microglia and production of inflammatory cytokines. In the mechanism exploration, we found that Lncenc1 could bind with the RNA binding protein (RBP) enhancer of zeste homologue 2 (EZH2), an identified contributor in microglial activation and neuropathic pain. Lncenc1 interacted with EZH2 and downregulated the expression of brain-specific angiogenesis inhibitor 1 (BAI1). Either inhibition of EZH2 or overexpression of BAI1 could reverse the effects of Lncenc1 overexpression on microglial activation and neuroinflammation. Finally, the Lncenc1-siRNA was intrathecally injected into pSNL mice, and its effects on neuropathic pain were evaluated. Knockdown of Lncenc1 attenuated the development and maintenance of mechanical and thermal hyperalgesia of pSNL mice, accompanied by an increase in BAI1 expression and decrease in inflammatory cytokines. In conclusion, Lncenc1 contributes to neuropathic pain by interacting with EZH2 and downregulating the BAI1 gene in mouse microglia.

BAI1 acts as a tumor suppressor in lung cancer A549 cells by inducing metabolic reprogramming via the SCD1/HMGCR module.

Brain-specific angiogenesis inhibitor 1 (BAI1) is an important tumor suppressor in multiple cancers. However, the mechanisms behind its anti-tumor activity, particularly the relationship between BAI1 and metabolic aberrant of a tumor, remained unveiled. This study aimed to investigate whether BAI1 could inhibit biological functions in lung cancer A549 cells and the critical regulating molecules that induce metabolic reprogramming. Immunohistochemistry staining was performed to analyze whether variations in the expression of BAI1 in tumor tissues contributes to poor prognosis of lung cancer. Overexpressed BAI1 (BAI1-OE-A549) and control (Vector-NC-A549) were generated by lentiviral transfection. Biological function assays (proliferation, apoptosis, colony formation, invasion and in vivo metastasis), as well as metabolic reprogramming (by the Warburg effect and the glycolytic rate), were performed in both groups. Our results indicated that lower levels of BAI1 contributed to poor prognosis of lung cancer patients. Furthermore, overexpressed of BAI1 dramatically inhibited proliferation, migration, invasion, colony formation and in vivo metastasis of A549 cells. The Warburg effect and the Seahorse assay revealed that BAI1-OE induced metabolism reprogramming by inhibiting the Warburg effect and glycolysis. Further exploration indicated that BAI1 induced metabolic reprogramming by upregulating stearoyl-CoA desaturase 1 (SCD1) and inhibited 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR). Our study revealed a novel mechanism through which BAI1 acted as tumor suppressor by inducing metabolic reprogramming via the SCD1 and HMGCR module.

Biological effects of eukaryotic recombinant plasmid pReceiver-M61-BAI-1 transfection on T24cells and HUVECs.

The aim of the current study was to investigate the biological effect on T24 cells and human umbilical vein endothelial cells (HUVECs) of transfection with brain-specific angiogenesis inhibitor-1 (BAI-1). The recombinant plasmid pReceiver-M61-BAI-1 was transfected into human superficial bladder tumor cells (T24) and HUVECs, in parallel with the vector control. mRNA and protein expression levels of BAI-1 were then detected by quantitative polymerase chain reaction (qPCR) and western blotting, respectively. Cell apoptosis of T24 cells and HUVECs prior and subsequent to transfection with BAI-1 was analyzed by flow cytometric analysis. Proliferation of T24 cells and HUVECs prior and subsequent to transfection of BAI-1 was assessed by the MTT method. T24 cells and HUVECs transfected with pReceiver-M61-BA1-1 were classed as the experimental group; T24 cells and HUVECs transfected with p-Receiver-M61 were the control group. qPCR and western blotting methods confirmed that there was positive expression of BAI-1 in T24 cells and HUVECs transfected with pReceiver-M61-BAI-1, however BAI-1 was not expressed in T24 cells and HUVECs transfected with pReceiver-M61. The results of the MTT assay demonstrated that absorbance was markedly reduced in HUVECs at 12, 48 and 72 h subsequent to transfection with pReceiver-M61-BAI-1 when compared with that of the control group and in T24 cells transfected with p-Receiver-M61-BAI-1. Furthermore, flow cytometry results also indicated that the apoptotic rate of HUVECs transfected with p-Receiver-M61-BAI-1 was significantly increased compared with that of the control group and T24 cells transfected with p-Receiver-M61-BAI-1. BAI-1 was observed to markedly inhibit the proliferation of vascular endothelial cells in vitro, however, no direct inhibition by BAI-1 was observed in T24 cells. In conclusion, BAI-1 is suggested to be a potential novel therapautic target for the inhibition of tumor neovascularization.

Expression of brain‑specific angiogenesis inhibitor‑1 and association with p53, microvessel density and vascular endothelial growth factor in the tissue of human bladder transitional cell carcinoma.

The aim of the present study was to investigate the expression levels of brain‑specific angiogenesis inhibitor‑1 (BAI‑1) in bladder transitional cell carcinoma (BTCC) at different stages and the mechanism by which it inhibits tumor endothelial cell proliferation. Normal bladder mucosa biopsy specimens were obtained as the control group, and human BTCC biopsy specimens were used as the study group. Immunohistochemical assays were used to detect the expression levels of BAI‑1, vascular endothelial growth factor (VEGF) and mutant p53, in addition to microvessel density (MVD) in the tissues. Western blotting was used to analyze the differential expression of BAI‑1 in the two samples. Statistical analysis was performed, which indicated that BAI‑1 expression levels in the normal bladder mucosa group were significantly higher than those in the BTCC group and were associated with clinical staging. BAI‑1 levels in the T1 stage BTCC tissues were higher than those in the T2‑4 stage BTCC tissues (P<0.05). BAI‑1 expression levels were negatively correlated with those of VEGF (r=‑0.661, P<0.001), mutant p53 (r=‑0.406, P=0.002) and with the MVD (r=‑0.675, P<0.001). BAI‑1 may be involved in the negative regulation of BTCC microvascular proliferation, and its expression may be associated with a reduction in p53 mutations.

CS-38 * BAI1 IS A NEW TUMOR SUPPRESSOR IN MEDULLOBLASTOMA

Brain-specific Angiogenesis Inhibitor 1 (BAI1) is a seven transmembrane G protein-coupled receptor (GPCR) with potent anti-angiogenic and anti-tumorigenic properties in gliomas. Our novel findings show that BAI1 expression is significantly reduced in human medulloblastoma (MB) by epigenetic mechanisms, leading us to hypothesize that loss of expression of BAI1 may favor tumor development during cerebellar development. To test this hypothesis, we generated a Bai1 knockout (KO) mouse and detected aberrant activation of Sonic hedgehog signaling and a thicker external granular layer during early postnatal cerebellum development. Furthermore, upon crossing the Bai1 KO mice with mice heterozygous for patched 1 (ptc1 + /-), we found that deficiency of Bai1 dramatically accelerated MB tumorigenesis, the first demonstration that a reduction in Bai1 dosage can promote MB formation in vivo. Moreover, restoration of BAI1 expression in human MB cells inhibited cell growth both in vitro and in vivo. These results support that BAI1 is a novel tumor suppressor for MB and that down-regulation of BAI1 in the cerebellum may drive inappropriate downstream growth signaling and contribute to neoplastic transformation leading to the formation of MB. To further elucidate the molecular mechanisms, we are currently exploring the Bai1 downstream signaling involved in MB tumorigenesis and will present the related findings. Our results also suggest that restoration of BAI1 expression may represent a novel therapeutic intervention for MB. Specifically, we demonstrate that small molecule epigenetic inhibitors of either EZH2 or MBD2 can reactivate BAI1 expression. Taken together, our novel findings provide insight into the neurobiological mechanisms underlying MB tumorigenesis and provide the rationale for the use of epigenetic therapeutics against MB.

Expression of brain-specific angiogenesis inhibitor 1 is inversely correlated with pathological grade, angiogenesis and peritumoral brain edema in human astrocytomas

As the most common intracranial malignant neoplasms, astrocytomas are characterized by high neovascularization and severe peritumoral brain edema (PTBE). Angiogenesis is a prerequisite for the growth of solid tumors, including astrocytoma, and brain-specific angiogenesis inhibitor 1 (BAI1) is a novel angiogenesis inhibitor. In the present study, the expression levels of BAI1, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were investigated using immunohistochemical methods in 90 human brain astrocytoma specimens of various pathological grades and in 11 normal human brain tissues. Vascular endothelial cells were stained for CD105 and the microvessel density (MVD) was assessed. The volume of astrocytoma and PTBE in each case was evaluated by magnetic resonance imaging (MRI). The results showed that BAI1 was highly expressed in the normal brain tissues, but that the expression decreased with the rising pathological grades of astrocytoma, MVD number and PTBE, indicating that BAI1 expression was inversely correlated with these factors. Furthermore, it was observed that the expression of VEGF and bFGF were inversely correlated with BAI1 expression in the human brain astrocytomas. These results indicate that the BAI1 gene may be used as a marker of decreased tumor progression and tumoral neovascularization, as well as PTBE.

Brain-specific angiogenesis inhibitor-1 expression in astrocytes and neurons: Implications for its dual function as an apoptotic engulfment receptor

Brain-specific angiogenesis inhibitor-1 (BAI1) is a transmembrane protein highly expressed in normal brain that has been ascribed two apparently distinct functions: inhibition of angiogenesis and recognition and engulfment of apoptotic cells by phagocytes. A previous localization study reported BAI1 expression only in neurons. Because a phagocytic function of BAI1 could be important for neuroglial antigen processing and presentation, we performed immunolocalization studies in adult mouse brain and cultured neural cells, using a pair of antibodies directed against N- and C-terminal epitopes. BAI1 immunoreactivity is enriched in gray matter structures and largely excluded from myelinated axon tracts. Neuronal BAI1 expression was readily detectable in the cerebellar molecular layer as well as in primary hippocampal cultures. In some brain regions, especially olfactory bulb glomeruli, BAI1 was expressed by GFAP-positive astrocytes. Cultured cortical astrocytes show small (∼0.4 μm 2) BAI1 immunoreactive membrane puncta as well as prominent focal adhesion localization in a subset of cells. In mixed neuronal–glial cultures, BAI1-expressing astrocytes frequently contained engulfed apoptotic debris. Cultured astrocytes engulfed apoptotic targets, and BAI1 showed accumulation within the phagocytic cup. We hypothesize that glial BAI1 may subserve an engulfment function in adult brain regions such as olfactory bulb with ongoing apoptotic turnover, whereas neuronal-derived BAI1 may serve primarily as an anti-angiogenic factor in the mature neuropil.

BAI1 is an engulfment receptor for apoptotic cells upstream of the ELMO/Dock180/Rac module

Engulfment and subsequent degradation of apoptotic cells is an essential step that occurs throughout life in all multicellular organisms. ELMO/Dock180/Rac proteins are a conserved signalling module for promoting the internalization of apoptotic cell corpses; ELMO and Dock180 function together as a guanine nucleotide exchange factor (GEF) for the small GTPase Rac, and thereby regulate the phagocyte actin cytoskeleton during engulfment. However, the receptor(s) upstream of the ELMO/Dock180/Rac module are still unknown. Here we identify brain-specific angiogenesis inhibitor 1 (BAI1) as a receptor upstream of ELMO and as a receptor that can bind phosphatidylserine on apoptotic cells. BAI1 is a seven-transmembrane protein belonging to the adhesion-type G-protein-coupled receptor family, with an extended extracellular region and no known ligands. We show that BAI1 functions as an engulfment receptor in both the recognition and subsequent internalization of apoptotic cells. Through multiple lines of investigation, we identify phosphatidylserine, a key 'eat-me' signal exposed on apoptotic cells, as a ligand for BAI1. The thrombospondin type 1 repeats within the extracellular region of BAI1 mediate direct binding to phosphatidylserine. As with intracellular signalling, BAI1 forms a trimeric complex with ELMO and Dock180, and functional studies suggest that BAI1 cooperates with ELMO/Dock180/Rac to promote maximal engulfment of apoptotic cells. Last, decreased BAI1 expression or interference with BAI1 function inhibits the engulfment of apoptotic targets ex vivo and in vivo. Thus, BAI1 is a phosphatidylserine recognition receptor that can directly recruit a Rac-GEF complex to mediate the uptake of apoptotic cells.

New Candidates for the PS Receptor

Prompt removal of cells that die by programmed cell death, or apoptosis, is a key mechanism by which this intentional cell death response does not lead to inflammation. Phosphatidylserine (PS) is a membrane lipid that is exposed on the surface of apoptotic cells, where it is believed to be a key signal for the recognition of such dying cells by phagocytosing cells. Two groups report the identification of proteins that bind PS and appear to be important for recognition and phagocytosis of apoptotic cells. Park et al . identified brain-specific angiogenesis inhibitor 1 (BAI1)--a seven-transmembrane-domain protein with an extended extracellular region containing thrombospondin repeats (TSR) and an RGD domain--in a yeast two-hybrid screen for proteins that interacted with Rac and its guanine nucleotide exchange factor (GNEF), the EMLO and Dock180 complex, which are part of the signaling cascade that triggers the changes in the actin cytoskeleton associated with phagocytosis. Forced expression of BAI1 in nonphagocytic cells or in macrophages enhanced uptake of apoptotic thymocytes or beads mimicking apoptotic cells. (BAI1 was detected in untransfected human monocytes and macrophages, macrophage cell lines, spleen, and bone marrow.) Annexin V, which binds PS, prevented BAI1-stimulated phagocytosis of apoptotic cells, as did exposure of the cells to a BAI1 fragment containing the RGD and TSR domains, but not one lacking the TSR domain. The BAI1 TSR domain fragment also blocked phagocytosis of labeled beads when co-injected into the peritoneum of mice. Depletion of BAI1 in primary mouse astrocytes decreased phagocytosis of the beads or apoptotic thymocytes. Miyanishi et al . screened a panel of antibodies against mouse peritoneal macrophages and found that an antibody that recognized T cell immunoglobulin- and mucin-domain-containing molecule 4 (Tim4) inhibited PS-dependent engulfment of apoptotic cells. Tim4 mRNA was detected in peritoneal cells, spleen, lymph nodes, and salivary glands, and forced expression of Tim4, which has a single transmembrane domain, in nonphagocytic cells promoted the phagocytosis of apoptotic cells. Injection of the antibody that recognized Tim4 in mice followed by treatment to induce apoptosis in the thymus resulted in impaired phagocytosis of the apoptotic cells and the development of autoantibodies. A fusion protein between the Tim4 extracellular domain and the Fc domain of antibody receptors (Tim4-Fc) bound to apoptotic cells or to PS spots on nitrocellulose filters. Fusion proteins containing the Tim4 or Tim1 IgV domain bound to microtiter plates coated in PS. However, the same domains of the Tim2 and Tim3 family members showed no such binding, nor did the full-length proteins promote apoptotic cell phagocytosis when overexpressed. Exosomes, which are membrane fragments released from cells that may mediate cell communication, also have PS on the surface, and cells expressing either Tim4 or Tim1 bound exosome-like vesicles (based on gold-labeling and electron microscopy). PS appeared to promote heterophilic and homophilic interactions between Tim4 and Tim1. The authors suggest that Tim1 and Tim4 may serve as PS receptors involved in recognition of both apoptotic cells and exosomes. D. Park, A.-C. Tosello-Trampont, M. R. Elliott, M. Lu, L. B. Haney, Z. Ma, A. L. Klibanov, J. W. Mandell, K. S. Ravichandran, BAI1 is an engulfment receptor for apoptotic cells upstream of the ELMO/Dock180/Rac module. Nature 450 , 430-434 (2007). [PubMed] M. Miyanishi, K. Tada, M. Koike, Y. Uchiyama, T. Kitamura, S. Nagata, Identification of Tim4 as a phosphatidylserine receptor. Nature 450 , 435-439 (2007). [PubMed]

Characterization of mouse brain-specific angiogenesis inhibitor 1 (BAI1) and phytanoyl-CoA alpha-hydroxylase-associated protein 1, a novel BAI1-binding protein

Previously, PAHX-AP1 (PAHX-associated protein 1) was isolated as a novel protein to interact with Refsum disease gene product (phytanoyl-CoA alpha-hydroxylase, PAHX) and specifically expressed in mouse brain. PAHX-AP1 is also suggested to be involved in the development of the central neurologic deficits of Refsum disease. To clarify its function, we have searched for proteins that associate with PAHX-AP1 via yeast two-hybrid system. We found that PAHX-AP1 interacts with the cytoplasmic region of human brain-specific angiogenesis inhibitor 1 (hBAI1), and isolated murine homolog of hBAI1. Structural analysis of the PAHX-AP1 with three reported hBAI-associated proteins (BAP) revealed no homology among them, and we designated PAHX-AP1 as BAP4. The ability of BAP4 to interact with BAI1 was confirmed by pulling-down BAI1 with GST-BAP4 protein and immunoprecipitation study using brain lysate. Northern and Western blot analyses demonstrated a unique pattern of BAI1 expression in the brain. The peak level of BAI1 was observed 10 days after birth. In situ hybridization analyses of the brain showed the same localization of BAI1 as BAP4, such as most neurons of cerebral cortex, hippocampus, and V, VI, VII, VIII, and XII nuclei. Because BAI1 possessed thrombospondin-type 1 repeats in its extracellular region, changes of BAI1 expression were examined in the focal cerebral ischemia model. The BAI1 expression decreased on the ischemic side after 24 h but BAP4 was not changed after the time-course of ischemia. Our results indicate that expression and localization of BAI1 in the brain is correlated with BAP4, and that BAI1 is involved in inhibition of angiogenesis and neuronal differentiation.

Comparative study of angiostatic and anti-invasive gene expressions as prognostic factors in gastric cancer

Genes involving angiogenesis and metastasis play an important role in the progression and infiltration of cancer. We examined the expressions of various angiostatic and potential invasion/metastasis suppressor genes through RT-PCR analyses in 32 gastric cancer specimens with or without distant metastasis. The expressions of the invasion/metastasis suppressor, nm23 and E-cadherin increased much more in the cancer tissue (CT) and metastatic lymph node (MLN) than in the extraneoplastic mucosa (EM) and non-metastatic lymph node (NLN), respectively. The expressions of the angiostatic factor, angiopoietin 2 and thrombospondin 2 increased in the CT and MLN as compared with the EM and NLN, respectively. The newly cloned angiostatic factor, brain-specific angiogenesis inhibitor 1 (BAI1) decreased much more in the CT and MLN than the EM and NLN, respectively. However, BAI1 increased in the CT compared with the EM among the patients with poor prognosis and distant metastasis, such as liver or peritoneum. The expressions of the invasive factor, matrix metalloproteinase-2 and its suppressor, tissue inhibitor metalloproteinase-2 (TIMP-2) increased in the CM as compared with the EM, but the increased expression pattern of these genes in the CT became blunted among the patients with good prognosis. Our results indicate that BAI1 and TIMP-2 expressions in the extraneoplastic mucosa and non-metastatic lymph nodes were not suppressed in the patients with good prognosis, but increased expressions of angiopoietin 2, thrombospondin 2, TIMP-2, nm23 and E-cadherin in the tumor tissue did not lead to a long survival after operation. It is suggested that the extent of BAI1 and TIMP-2 expression in the gastric mucosa may be an important prognostic factor for predicting survival in gastric cancer.

Vascularization is decreased in pulmonary adenocarcinoma expressing brain-specific angiogenesis inhibitor 1 (BAI1).

Brain-specific angiogenesis inhibitor 1 (BAI1) is a novel angioinhibitory factor. We examined BAI1 gene expression in 48 pulmonary adenocarcinoma specimens by RT-PCR. Vascular density (number and measurement area) was immunohistochemically evaluated in tumor specimens using anti-CD34 monoclonal antibody. BAI1 gene expression was detected in 38 of 48 pulmonary adenocarcinomas (79. 2%). Vascular number and measurement area were significantly decreased in the BAI1-positive pulmonary adenocarcinomas (19.3+/-4. 4/microm2 and 1.7+/-0.6%) as compared with those in the BAI1-negative carcinomas (75.5+/-42.7/microm2 and 5.5+/-1.5%) (Mann-Whitney U-test, p=0.0017). These results suggest that BAI1 expression may inhibit stromal vascularization in pulmonary adenocarcinoma.

Expression of angiostatic factors in colorectal cancer.

Angiogenesis plays an important role in growth and proliferation of cancer. Various angiogenic and angiostatic factors regulate angiogenesis. We examined expression of genes encoding various angiostatic factors: thrombospondin 1 (TSP1), thrombospondin 2 (TSP2), brain-specific angiogenesis inhibitor 1 (BAI1) and angiopoietin 2 (AGP2) in 62 colorectal cancers and 40 samples of extraneoplastic colon mucosa. The expression of the angiostatic factors TSP2 and AGP2 were significantly increased in the cancerous mucosa as compared to these in extraneoplastic mucosa (o2 test; p<0. 0001, and Fisher's exact test; p<0.0001), while the increase in TSP1 expression was not significant. BAI1 expression was slightly decreased in the cancer tissue. These results suggested that specific types of angiostatic factors might have protective roles against cancer cell proliferation via dormancy due to hyponutrition caused by decreased vascularity.