7070

THY1

Thy-1 cell surface antigen;THY1;Thy-1 cell surface antigen

CDw90|Thy-1 T-cell antigen|thy-1 antigen|thy-1 membrane glycoprotein

11q23.3

protein-coding

tumor-initiating cells (TIC), also known as cancer stem cells, are regarded widely as a specific subpopulation of cells needed for cancer initiation and progression. TICs have yet to be identified in esophageal tumors that have an increasing incidence in developed countries. Here, we report a CD90(+) cell population found in esophageal squamous cell carcinoma (ESCC), which is endowed with stem cell-like properties and high tumorigenic and metastatic potential. mRNA profiling of these cells suggested pathways through which they drive tumor growth and metastasis, with deregulation of an Ets-1/MMP signaling pathway and epithelial-mesenchymal transition figuring prominently. These cells possessed higher self-renewal activity and were sufficient for tumor growth, differentiation, metastasis, and chemotherapeutic resistance. CD90(+) TICs were isolated and characterized from ESCC clinical specimens as well as ESCC cell lines. In freshly resected clinical specimens, they represented a rare cell population, the levels of which correlated with strong family histories and lymph node metastasis. Our results prompt further study of this CD90(+) population of esophageal TICs as potential therapeutic targets.

The cell adhesion molecule Thy-1 (CD90) mediates the adhesion of melanoma cells to activated human endothelial cells (EC) via the interaction with the alphavbeta3-integrin on the tumor cells in vitro. Here, we report a strong expression of Thy-1 on both blood vessel and lymphatic EC in melanoma and melanoma metastases. Vascular endothelial growth factor and tumor necrosis factor-alpha were identified as inducers of Thy-1 expression on EC in vitro. The physiological role of Thy-1 for lymphogenic and hematogenic metastasis of melanoma cells was substantiated in an experimental metastasis model using B16/F10 melanoma cells. Mice lacking Thy-1 showed markedly diminished experimental lung metastasis after injection of B16/F10 melanoma cells compared to wild-type littermate controls. In addition, on generation of a primary subcutaneous tumor, metastasis to regional lymph nodes was clearly reduced in Thy-1(-/-) mice. However, Thy-1 deletion did not affect subcutaneous primary tumor growth, tumor-induced recruitment of inflammatory cells or T cells, angiogenesis, or T-cell activation. In conclusion, Thy-1 contributes to metastasis of melanoma cells by mechanisms likely involving a Thy-1-mediated adhesion of melanoma cells to EC.

OBJECTIVE: The purpose of this study was to investigate the clinical significance of THY1 protein expression in epithelial ovarian cancer. METHODS: Immunohistochemistry (IHC) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining were used to detect the protein expression of THY1, Ki67 and cell apoptosis in 76 epithelial ovarian cancers by tissue microarray. The correlation between THY1 expression and patients clinical features was analyzed. RESULTS: Of the 76 epithelial ovarian cancer samples, 64 were informative for IHC and TUNEL assays and 42 (65.6%) among them showed down-regulated/loss expression of THY1 protein. A significant positive correlation of THY1 protein expression with clinical stage and distant metastasis was observed in this ovarian cancer cohort (P < 0.05). The more advanced the tumor stage, the more frequency of loss expression of THY1 protein. In addition, the mean positive rate of Ki67 staining in tumors with down-regulated/loss expression of THY1 was 33.7% +/- 3.5%, significantly higher than that in the tumors with normal expression of THY1 (17.3% +/- 6.1%, P = 0.0027). However, no significant correlation was observed between THY1 protein expression and tumor cell apoptosis as well as patients survival in this series (P > 0.05). CONCLUSION: Down-regulated/loss expression of THY1 protein in epithelial ovarian cancer is significantly correlated with cancer cell proliferation and metastasis in the epithelial ovarian cancer, and it may be used as one of the new molecular biomarkers to predict the disease progression in patients.