Search

One of the most critical issues to be solved in regard to cancer chemotherapy is the establishment of ways to predict the efficacy of anti-cancer drugs for individual patients. To develop a prediction system based on expression of specific genes, we analyzed expression profiles of mononuclear cells from 18 chronic myeloid leukemia (CML) patients who were treated with the tyrosine kinase inhibitor STI571. cDNA microarrays representing 23 040 genes identified 79 genes that were expressed differentially between responders and non-responders to STI571. On the basis of the expression patterns of 15 or 30 of these genes among the patients, we developed a "Prediction Score" system that could clearly separate the responder group from the non-responder group. Verification of this system using four additional ("test") cases succeeded in predicting the response of each of those four patients to the drug. These results provide the first evidence that gene-expression profiles can predict sensitivity of CML cells to STI571, and may eventually lead to the achievement of "personalized therapy" for this disease.

Immunohistochemical expression of PRAD1/cyclin D1 protein has been investigated in 106 tissue specimens of 104 cases of lymphoma, non-neoplastic lymphoid disorders and other hematologic malignancies by employing the monoclonal antibody 5D4 with formalin-fixed paraffin-embedded sections, using the microwave oven heating method. Positive neoplastic cells were found in 60 (74%) of 81 cases of non-Hodgkin's lymphoma. The positivity pattern was nuclear in 17 (85%) of 20 cases of mantle cell lymphoma in which cytoplasmic staining was also seen. This pattern of cyclin D1 positivity was in contrast to the negative staining of normal reactive mantle zones. In the other cases, positivity appeared to lie within the cell cytoplasm without nuclear staining, and most of the nodal follicular and diffuse B-cell lymphomas variously expressed PRAD1/cyclin D1. In contrast, the reaction was absent in a significant number of T-cell and extranodal B-cell lymphomas. Immunolocalization of PRAD1/cyclin D1 expression appears to be a useful diagnostic adjunct to discriminate mantle cell lymphoma from other non-Hodgkin's lymphomas.

A novel interleukin-2 (IL-2)-dependent T-cell line, WHN2, was established from a patient with adult T-cell leukemia (ATL) not associated with human T-cell leukemia virus type I (HTLV-I). Neither the original leukemic cells nor the WHN2 cells showed proviral integration in their cellular DNAs by Southern blot analysis. The surface phenotype showed that both the original leukemic cells and the WHN2 cells had a common phenotype of ATL, i.e., positive for CD2, CD4, human leukocyte antigen DR (HLA-DR) and CD25, but negative for CD8, a characteristic of helper/inducer T-cells. Most of the chromosomal abnormalities of the original leukemic cells were maintained in the WHN2 cell line. Furthermore, Southern blot analysis of the T-cell receptor beta-chain gene rearrangement revealed that the original leukemic cells and WHN2 cell line had identical patterns, suggesting that the WHN2 cell line was truly derived from the original leukemic cells. Dose-dependent growth on IL-2 was demonstrated, and at the maximal stimulation, the number of cells doubled within three days. This IL-2-dependent growth was inhibited by the simultaneous existence of anti-IL-2 receptor alpha and beta chain antibodies. These results indicate that the character of the WHN2 cell line is similar to that of the cell lines derived from ATL associated with HTLV-I. Thus, the HTLV-I-negative ATL cell line, WHN2, should be useful in the comparative study of the pathogenesis of ATL associated with or without HTLV-I.

Leukemic cells from four out of eight patients with adult T-cell leukemia (ATL) were successfully grown by cocultivation with HSC-I cells, a human skin cancer cell line, in the presence of interleukin-2. Three of these four cultures of growing cells showed rearrangement of the T-cell receptor beta-chain gene like the original leukemic cells in vivo, and also showed conservation of the patterns of HTLV-I integration of the original leukemic cells in vivo. Cell-to-cell contact between HSC-I cells and leukemic cells was not necessary for growth of the leukemic cells. The results indicate that some soluble growth factor secreted by HSC-I cells and interleukin-2 are required for the in vitro growth of leukemic cells from some patients with adult T-cell leukemia.