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T-cell large granular lymphocyte (LGL) leukemia is characterized by clonal expansion of CD3 ؉ CD8 ؉ cells. LeukemicLGLs correspond to terminally differentiated effector-memory cytotoxic T lymphocytes (CTLs) that escape Fasmediated activation-induced cell death (AICD) in vivo. The gene expression signature of peripheral blood mononuclear cells from 30 LGL leukemia patients showed profound dysregulation of expression of apoptotic genes and suggested uncoupling of activation and apoptotic pathways as a mechanism for failure of AICD in leukemic LGLs. Pathway-based microarray analysis indicated that balance of proapoptotic and antiapoptotic sphingolipid-mediated signaling was deregulated in leukemic LGLs. We further investigated sphingolipid pathways and found that acid ceramidase was constitutively overexpressed in leukemic LGLs and that its inhibition induced apoptosis of leukemic LGLs. We also showed that S1P 5 is the predominant S1P receptor in leukemic LGLs, whereas S1P 1 is downregulated. FTY720, a functional antagonist of S1P-mediated signaling, induced apoptosis in leukemic LGLs and also sensitized leukemic LGLs to Fasmediated death. Collectively, these results show a role for sphingolipidmediated signaling as a mechanism for long-term survival of CTLs.

Human endometrium is unique since it is the only tissue in the body that bleeds at regular intervals. In addition, abnormal endometrial bleeding is one of the most common manifestations of gynecological diseases, and is a prime indication for hysterectomy. Here, we report on a novel human gene, endometrial bleeding associated factor ( ebaf ), whose strong expression in endometrium was associated with abnormal endometrial bleeding. In normal human endometrium, this gene was transiently expressed before and during menstrual bleeding. In situ hybridization showed that the mRNA of ebaf was expressed in the stroma without any singificant mRNA expression in the endometrial glands or endothelial cells. The predicted protein sequence of ebaf showed homology with and structural features of the members of TGF-␤ superfamily. Fluorescence in situ hybridization showed that the ebaf gene is located on human chromosome 1 at band q42.1. Thus, ebaf is a novel member of the TGF-␤ superfamily and an endometrial tissue factor whose expression is associated with normal menstrual and abnormal endometrial bleeding.

BackgroundDNA microarray technology is a powerful technique that was recently developed in order to analyze thousands of genes in a short time. Presently, microarrays, or chips, of the cDNA type and oligonucleotide type are available from several sources. The number of publications in this area is increasing exponentially. ResultsIn this study, microarray data obtained from two different commercially available systems were critically evaluated. Our analysis revealed several inconsistencies in the data obtained from the two different microarrays. Problems encountered included inconsistent sequence fidelity of the spotted microarrays, variability of differential expression, low specificity of cDNA microarray probes, discrepancy in fold-change calculation and lack of probe specificity for different isoforms of a gene.ConclusionsIn view of these pitfalls, data from microarray analysis need to be interpreted cautiously.