No abstract

T-cell infiltration into human cancer tissues can be a manifestation of host immune responses to cancer cells. The present study was undertaken to explore the clinicopathological significance of intraepithelial CD8 þ T cells using 371 consecutively sampled human colorectal carcinomas. By univariate analysis, we noted that the survival curves by intraepithelial CD8 þ T cells became separated only after 1 to 2 years postoperation. Multivariate analyses revealed that the beneficial effect of this factor becomes significant only after a longer (more than 2 year), but not after a shorter (less than 2 year) follow-up period. Furthermore, the number of intraepithelial CD8 þ T cells was significantly higher in patients alive for more than 5 years than in patients who either died of cancer after a curative operation or patients who underwent a noncurative operation. Patients' cancer-specific death long after a curative operation is thought to be caused by the growth of micrometastases in other organs or near the primary sites. The effects of intraepithelial CD8 þ T cells, therefore, may be mediated by suppression of micrometastasis, rather than suppression of growth in the primary tumour. In conclusion, our data support a hypothesis on the presence of systemic immunosurveillance against micrometastasis of cancer cells.

No abstract

Vascular endothelial growth factor (VEGF) is a principal stimulator of angiogenesis. However, the downstream targets of VEGF in endothelial cells (ECs) are not entirely clarified. Survey of downstream targets of VEGF in human ECs identified a number of genes, including Down syndrome candidate region 1 (DSCR1). Here, we confirmed the inducible expression of DSCR1 in ECs by Northern and Western blottings. Moreover, VEGF-stimulated induction of DSCR1 was blocked by anti-VEGF receptor-2 monoclonal antibody (mAb), or the specific calcineurin inhibitors cyclosporin A and FK506. The expression of DSCR1 in ECs of neovessels was further shown by immunohistochemical analysis. We therefore examined whether DSCR1 played any roles in angiogenesis. The specific downregulation of DSCR1 expression by antisense oligonucleotide (AS-ODN) inhibited VEGF-stimulated migration of ECs as well as angiogenesis in vivo. AS-ODN inhibited the spreading of ECs on vitronectin, as well as on the immobilized anti-αvβ3 mAb, but not on anti-αvβ5 mAb. Moreover, AS-ODN inhibited tyrosine phosphorylation of focal adhesion kinase when ECs were plated on a vitronectin-coated dish. Immunoprecipitation followed by Western blotting showed the coimmunoprecipitation of DSCR1 and integrin αvβ3. These results suggest that DSCR1 is involved in angiogenesis by regulating adhesion and migration of ECs via the interaction with integrin αvβ3.

Previous epidemiologic and in vitro studies have indicated a potential involvement of estrogens in the pathogenesis of human colon carcinoma, but the precise roles of estrogens have remained largely unknown. Therefore, in this study, we first measured intratumoral concentrations of estrogens in 53 colon carcinomas using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS). Tissue concentrations of total estrogen [estrone (E(1)) + estradiol] and E(1) were significantly (2.0- and 2.4-fold, respectively) higher in colon carcinoma tissues than in nonneoplastic colonic mucosa (n = 31), and higher intratumoral concentrations of total estrogen and E(1) were significantly associated with adverse clinical outcome. Intratumoral concentration of total estrogen was significantly associated with the combined status of steroid sulfatase (STS) and estrogen sulfotransferase (EST), but not with that of aromatase. Thus, we subsequently examined the STS/EST status in 328 colon carcinomas using immunohistochemistry. Immunoreactivities for STS and EST were detected in 61% and 44% of the cases, respectively. The -/+ group of the STS/EST status was inversely associated with Dukes' stage, depth of invasion, lymph node metastasis, and distant metastasis and positively correlated with Ki-67 labeling index of the carcinomas. In addition, this -/+ group had significantly longer survival, and a multivariate analysis revealed the STS/EST status as an independent prognostic factor. Results from our present study showed that the STS/EST status of carcinoma tissue determined intratumoral estrogen levels and could be a significant prognostic factor in colon carcinoma, suggesting that estrogens are locally produced mainly through the sulfatase pathway and play important roles in the progression of the disease.