No abstract

The tumor suppressor p53 plays a crucial role in the cellular response to DNA damage by transcriptional activation of numerous downstream genes. Although a considerable number of p53 target genes have been reported, the precise mechanism of p53-regulated tumor suppression still remains to be elucidated. Here, we report a novel role of the DFNA5 gene in p53-mediated etoposide-induced cell death. The DFNA5 gene has been previously reported to be responsible for autosomal-dominant, nonsyndromic hearing impairment. The expression of the DFNA5 gene was strongly induced by exogenous and endogenous p53. The chromatin immunoprecipitation assay indicated that a potential p53-binding sequence is located in intron 1 of the DFNA5 gene. Furthermore, the reporter gene assay revealed that the sequence displays p53-dependent transcriptional activity. The ectopic expression of DFNA5 enhanced etoposide-induced cell death in the presence of p53; however, it was inhibited in the absence of p53. Finally, the expression of DFNA5 mRNA was remarkably induced by gammaray irradiation in the colon of p53(+/+) mice but not in that of p53(-/-) mice. These results suggest that DFNA5 plays a role in the p53-regulated cellular response to genotoxic stress probably by cooperating with p53.

Summary The immunohistochemical expression of c-kit proto-oncogene product in 57 breast cancer tissues was studied using anti-c-kit proto-oncogene product antibody in comparison with 20 normal breast tissues and 58 benign breast tumours. In normal breast tissues, the c-kit proto-oncogene product was strongly expressed on cell membrane and/or cytoplasm of alveolar and ductal cells. The immunoreactive score (IRS) of c-kit protooncogene product in normal mammary epithelia was 6.22 + 2.11 (mean + s.d.). In benign breast diseases, the ckit proto-oncogene product was detected heterogeneously with a reduced IRS (3.33+2.44). In breast cancer tissues, the expression of the immunoreactive c-kit proto-oncogene product was often deleted and the average IRS was significantly reduced compared to those of normal breast tissues or benign breast disease tissues. Among benign diseases, the average IRS of intraductal papilloma was significantly reduced (1.34+1.70) and the staining intensity and pattern were found to be similar to those seen in breast cancer. The results in this study suggested that the c-kit proto-oncogene product is correlated with the growth control or the differentiation of normal breast epithelium. Also, the loss of the expression of this protein may indicate the change of the signal transduction in relation to malignant transformation in human mammary epithelium.

The dynamic aspects of circulating cytokines and cytokine modulators and their relationship with development of multiple organ failure (MOF) in patients with acute pancreatitis were analyzed. All cytokine and C-reactive protein levels in the circulation were higher than those in the MOF group. In particular, plasma concentrations of soluble tumor necrosis factor receptors (sTNF-RI and sTNF-RII) were significantly higher in patients with MOF than in those without even at admission. Furthermore, plasma concentrations of sTNF-Rs and interleukin-1 (IL-1) receptor antagonist (IL-1ra) were much higher than those of their counterparts, TNFalpha and IL-beta, respectively. These results suggest that the plasma concentrations of sTNF-Rs are useful predictors for the development of MOF, and actions of TNF-alpha and IL-1beta could be regulated by their modulators (soluble receptor and receptor antagonist, respectively) in the pathologic condition of severe acute pancreatitis.

Abstract. The clinical significance of isolated tumor cells (ITC) circulating in the blood of patients with colorectal cancer is unclear. In this study, we investigated the relationship between the presence of ITC that express carcinoembryonic antigen (CEA) and/or cytokeratin 20 (CK20) transcripts in the blood and the clinicopathological findings and prognosis using the quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) assay. We studied peripheral blood and tumor drainage blood from 167 patients with colorectal cancer. Quantitative real-time RT-PCR assay was able to detect one tumor cell in 3x10 6 peripheral blood mononuclear cells. Applying a cut-off value, CEA and/or CK20 (CEA/CK20) were detected in 10.2% (17/167) of the patients' preoperative peripheral blood samples and 34.1% (57/167) of the patients' tumor drainage blood samples. In the relationship between the CEA/CK20 of the blood and the clinicopathological factors, a significant correlation was demonstrated between the positivity of marker genes and the depth of invasion, venous invasion, lymph node metastasis, liver metastasis or stage. The disease-free and overall survival of patients with CEA/CK20-positive peripheral or tumor drainage blood was significantly shorter than that of marker gene-negative patients. CEA/CK20 transcripts in tumor drainage blood were independent factors for prognosis in disease-free survival and overall survival. These results suggest that detecting CEA/CK20 mRNA in tumor drainage blood by real-time RT-PCR has prognostic value in patients with colorectal cancer. Large scale and longterm clinical studies are needed to confirm the prognostic value of genetically detecting ITC in the peripheral blood.