Interruption of p16 gene expression in adult T-cell leukaemia/lymphoma: clinical correlation.

We previously reported that p16 gene deletion is involved in the development and progression of adult T-cell leukaemia/lymphoma (ATLL). To further investigate the significance of this gene in ATLL, we examined its expression status in 63 patients. Samples were analysed at DNA, mRNA and protein levels using real-time polymerase chain reaction (PCR), reverse transcription (RT)-coupled real-time PCR and Western blot respectively.

Significance of HTLV-1 proviral load quantification by real-time PCR as a surrogate marker for HTLV-1-infected cell count.

We developed a real-time (RT) PCR quantitative assay to measure the level of the integrated viral genome of HTLV-1 in host peripheral blood-mononuclear cells (PB-MNC) from healthy carriers and patients with adult T-cell leukemia (ATL). All of the clinical specimens were serologically and molecularly characterized by enzyme-linked immunosorbent assay (ELISA) and Southern blot hybridization (SBH) analyses. The assay system for quantifying the proviral copy level was sensitive, accurate, and reproducible over a wide range of density from 100 to 0.

Possible attenuation of fas-mediated signaling by dominant expression of caspase-8 aberrant isoform in adult T-cell leukemia cells.

The Fas up-regulated in adult T-cell leukemia (ATL) cells is usually the wild-type protein and is usually functional, at least in vitro. However, primary ATL cells, in contrast to ATL cell lines, are not necessarily susceptible to anti-Fas-induced apoptosis. To clarify the mechanism tuning the apoptotic signal transduction initiated by the activation caspase-8 in ATL cells and ATL cell lines, we examined the expression profile of caspase-8, of which there are at least 8 isoforms at the messenger RNA (mRNA) level with the potential to finely tune the signal transduction.

Aberrant expression of caspase cascade regulatory genes in adult T-cell leukaemia: survivin is an important determinant for prognosis.

Derangement of either apoptosis or cell division is known to play an important role in tumorigenesis. Fas-mediated apoptosis on normal and leukaemic T cells is finely tuned by inhibitory proteins, such as FAP-1, FLIP and survivin, and defective caspase isoform which can attenuate the function of its intact caspase as a decoy molecule. However, complex involvement of such inhibitors in tumour biology relating to apoptotic pathology remains unclear in the neoplasms.

Real-time polymerase chain reaction for quantification of HTLV-1 proviral load: application for analyzing aberrant integration of the proviral DNA in adult T-cell leukemia.

We describe the establishment of a real-time polymerase chain reaction (PCR) assay for the quantitative estimation of human T-cell leukemia virus type 1 (HTLV-1) proviral load using a LightCycler Technology (Roche Diagnostics, Mannheim, Germany) instrument. Proviral DNA level represents a measure of the integrated viral genome in host cells, so we applied this technique to evaluate the tumor burden in adult T-cell leukemia (ATL) patients with aberrant integration patterns of HTLV-1 detected by standard Southern blot hybridization (SBH) analysis. In 14 of our 15 ATL cases with 2 or more bands detected by SBH analysis, the ATL cells were shown to harbor multiple copies of the provirus within 1 ATL cell.

[Characteristics of plasma DNA and its application for detection of K-ras gene mutation].

DNA diagnosis is useful and significant for clinical oncology, but its use is limited due to a difficulty in preparing tumor-derived DNA materials. To overcome this problem, we investigated the characterization of plasma DNA and it application to successfully detecting K-ras mutation at codon 12 in normal persons, hematopoietic neoplasms, and solid tumors. The range of plasma DNA in each group was 15.

Qualitative and quantitative characterization of Fas (CD95) expression and its role in primary human acute leukemia cells.

Fas antigen, a cell surface molecule, directly mediates apoptosis, and is expressed on a limited number of human tissues. Blood or bone marrow samples from patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL) and mixed leukemia were examined qualitatively and quantitatively for the expression of Fas as well as its function using flow cytometry and the annexin V staining method. Fas expression was flow cytometrically unimodal with heterogeneous density, and showed quantitatively characteristic features in different diseases: undetectable in mixed leukemia, faint to weak in ALL, low in M0 and M1, and variable (low to strong) in M2, M3, M4, and M5.

[Monoclonal analysis in B-cell neoplasms by the semi-nested polymerase chain reaction using consensus primers].

Monoclonality on B-cells is well known to be determined on the basis of presence of a rearranged-IgH gene, which is detected by Southern blot hybridization (SBH) remaining to be elucidated in respects of not only time-consumed, labour and cost benefit and also the use of much DNA samples. Alternative to this SBH, we examined the clinical usefulness of monoclonal analysis by the polymerase chain reaction technique which amplifies rearranged-CDR III region of IgH gene (IgH-PCR). The detective sensitivity of the IgH-PCR was different dependently upon each analysis for amplified products, namely 10(-2) per mononuclear cells in agarose gel analysis and 10(-3) in polyacrylamide gel and single strand conformation polymorphism analysis (PAGE and SSCP).