Ichiro Kubonishi

BRD4 bromodomain gene rearrangement in aggressive carcinoma with translocation t(15;19).

Translocation t(15;19)(q13;p13.1) defines a lethal midline carcinoma arising adjacent to respiratory tract in young people. To characterize molecular alterations responsible for the distinctly aggressive biological behavior of this cancer, we mapped the chromosome 15 and 19 translocation breakpoints by fluorescence in situ hybridization (FISH) and Southern blotting. To evaluate preliminarily the frequency, anatomical distribution, and histological features of t(15;19) cancer, we developed a FISH assay for paraffin sections. Our findings reveal a novel oncogenic mechanism in which the chromosome 19 translocation breakpoint interrupts the coding sequence of a bromodomain gene, BRD4. These studies implicate BRD4 as a potential partner in a t(15;19)-associated fusion oncogene. In addition, we localized the chromosome 15 breakpoint to a 9-kb region in each of two cases, thereby identifying several candidate oncogenes which might represent the BRD4 fusion partner. FISH evaluation of 13 pediatric carcinomas revealed t(15;19) in one of four sinonasal carcinomas, whereas this translocation was not detected in thymic (n = 3), mucoepidermoid (n = 3), laryngeal (n = 2), or nasopharyngeal (n = 1) carcinomas. Our studies shed light on the oncogenic mechanism underlying t(15;19) and provide further evidence that this highly lethal cancer arises from respiratory mucosa.

Human B cell, T cell and null cell leukaemic cell lines derived from acute lymphoblastic leukaemias

CONTINUOUS culture of human leukaemic cells is still a difficult task, although several leukaemic cell lines have been derived from patients with acute and chronic myelogenous leukaemia1,2 and acute lymphoblastic leukaemia (ALL) (refs 3–6). We describe here B-cell, T-cell and null-cell leukaemic cell lines newly established from three patients with ALL.

High serum levels of CA125 and interleukin-6 in a patient with Ki-1 lymphoma

We report a 53‐year‐old‐man with an aggressive Ki‐1 lymphoma who had high serum CA125, a marker protein of the epithelial ovarian cancer, and interleukin‐6 (IL‐6) concentrations. Both CA125 and IL‐6 levels decreased after chemotherapy and elevated with disease progression. The patients lymphoma cells obtained before chemotherapy grew continuously in vitro, were IL‐6 dependent and were found to secrete CA125 in culture medium. These results indicate that CA125 can be secreted by Ki‐1 lymphoma cells and IL‐6 may promote the growth of Ki‐1 lymphoma cells.

The establishment of Epstein-Barr virus nuclear antigen-positive (SP-50B) and Epstein-Barr virus nuclear antigen-negative (SP-53) cell lines with t(11;14)(q13;q32) chromosome abnormality from an intermediate lymphocytic lymphoma

Two lymphoma cell lines, SP‐50B and SP‐53, were established from peripheral blood of a 58‐year‐old woman with leukemic conversion of intermediate lymphocytic lymphoma. These cell lines grew in suspension with or without forming clumps of cells. SP‐50B was morphologically similar to the common Epstein‐Barr (EB) virus‐transformed lymphoblastoid cell lines and was positive for EB virus nuclear antigen (EBNA), whereas SP‐53 closely resembled the patients lymphoma cells and was negative for EBNA. Both cell lines expressed the same phenotypic markers as original lymphoma cells (CpIg+, SmIg+, OKIaI+, Leu12+) and possessed t(11;14)(q13;q32) chromosome translocation. These results indicate that although morphologically different, SP‐50B and SP‐53 were both derived from patients lymphoma cells. The long‐term cultivation of EBNA‐positive and EBNA‐negative B‐cell lymphoma lines from a single donor has not been previously reported. These cell lines would provide useful tools for studying the oncogenic role of EB virus and bcl‐1 oncogene that is located on chromosome 11q13.

Establishment of a clonal cell line producing granulocyte colony-stimulating factor and parathyroid hormone-related protein from a lung cancer patient with leukocytosis and hypercalcemia.

Squamous cell lung carcinoma cells obtained from a patient who presented with leukocytosis and hypercalcemia were transplanted into nude mice anda serially transplantable cell line, OKa‐N‐1, was established. The nude mice transplanted with OKa‐N‐1 cells displayed leukocytosis and hypercalcemia. Serum levels of granulocyte colony‐stimulating factor (G‐CSF) and parathyroid hormone‐related protein (PTHrP) were both elevated in these mice. In vitro cultivation of this tumor cell line gave rise to a clonal cell line, OKa‐C‐1. Nude mice transplanted with the OKa‐C‐1 cell line also showed leukocytosis and hypercalcemia with high serum G‐CSF and PTHrP levels. The culture supernatant of OKa‐C‐1 contained high levels of G‐CSF and PTHrP. Immunohistochemical studies showed the expression of PTHrP in OKa‐C‐1 cells. Reverse transcription polymerase chain reaction revealed the presence of G‐CSF and PTHrP mRNA in this cell line. Dexamethasone treatment inhibited the transcription of G‐CSF and PTHrP genes. This new human squamous carcinoma cell line, OKa‐C‐1, would be useful for studying the mechanism of simultaneous production of G‐CSF and PTHrP and their control in cancer patients with leukocytosis and hypercalcemia.

Identification of integrated human herpesvirus 6 DNA in early pre-B cell acute lymphoblastic leukemia

Identification of integrated human herpesvirus 6 DNA in early pre-B cell acute lymphoblastic leukemia

Lung squamous cell carcinoma producing both parathyroid hormone-related peptide and granulocyte colony stimulating factor

An autopsy case of a 61 year old male with primary squamous call carcinoma of the lung with associated marked leukocytosls and hypercalcemla Is reported. High levels of serum parathyroid hormone‐related peptide (PTHrP) and granulocyte colony stimulating factor (GCSF) were detected. The tumor cells distinctly showed positive cytoplasmic knmunoreactions with anti‐PTHrP and anti‐GCSF antibodies. Marked granulocytosls and thin bony trabeculae lacking osteoblasts were observed in the vertebral bone. Calcium deposits were found In the proximal tubules of the kidneys. Infarcts were seen as a result of fibrin thrombosis of the splenic artery. The tumor was successfully transplanted into nude mice in which the high levels of serum PTHrP and GCSF were reproduced. These results indicate that the tumor simultaneously produced both PTHrP and GCSF causing the paraneoplastic syndromes of hypercalcemia and ieukocytosis.

New variant translocation (1;8;21) in a case of acute myeloblastic leukemia (M2)

A new translocation involving chromosome #1, #8, and #21 in a patient with type M2 acute myeloblastic leukemia is reported. The breakpoint of #1 in this case was at band p13 and differed from that in two previously reported cases of t(1;8;21) involving the long arm of #1. A key event leading to the development of the M2 phenotype appears to be a break at band q22 of #8 with associated translocation of the terminal end of the long arm of #21.

Establishment of B-lymphoid cell lines retaining cytogenetic characteristics of Bloom syndrome

The present study describes the establishment of and chromosomal changes in B-lymphoid cell lines from cells of Bloom syndrome (BS) patients using Epstein-Barr virus (EBV). Even though PHA-stimulated BS lymphocytes from all five patients studied showed high levels of sister chromatid exchange (SCE), three EBV-transformed BS-B-lymphoid cell lines had normal levels of SCE and two yielded two types of cell populations, i.e., one with increased SCE and chromosome instability (including breaks and quadriradials) and another with normal levels of SCE and without structural aberrations. The karyotypic abnormalities, as observed in the BS lines have not been seen in the cells of any established normal B-lymphoid lines transformed by EBV and strongly suggest that the chromosome abnormalities in the BS--B-cell lines with abnormal karyotypes originated in vivo and not through an in vitro effect of EBV. Furthermore, in the EBV-transformed B-cell lines, we found quadriradial formation between sister chromosomes during endomitoses instead of between homologous chromosomes, strongly suggesting that quadriradial formation may be closely related to SCE. The coexistence in BS subjects of abnormal and normal populations of cells with respect to the number of SCE awaits explanation.

Translocation (10;11)(p13;q13) and MLL Gene Rearrangement in a Case of AML (M5a) with Aggressive Leukemia Cutis

A male patient with a secondary acute monocytic leukemia whose leukemia cells had a t(10;11)(p13;q13) chromosomal abnormality is described. Gene analysis disclosed that the patients leukemia cells had MLL gene rearrangement. His leukemia cells responded poorly to chemotherapy, and the patient developed an unusual aggressive leukemia cutis. A t(10;11)(p13;q13) chromosomal abnormality that expresses MLL gene rearrangement has not been reported previously in secondary leukemia.