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We previously found that cases of typical B-chronic lymphocytic leukemia (CLL), atypical B-CLL with t(11;14) and mantle cell lymphomas characterized by rapid progression of the disease and resistance to therapy, had mutations of the TP53 gene. In this paper, abnormalities of the TP53 gene were investigated in two cases of prolymphocytic leukemia, one with t(11;14)(q13;q32), evolving from atypical CLL (patient 1), and one presenting as a de novo condition (patient 2). TP53 DNA was investigated by Southern blot and PCR-SSCP analysis, and TP53 expression was investigated by Northern blot analysis and immunocytochemistry. C-MYC and BCL-1/PRAD1 gene expression were also investigated. Restriction enzyme analysis of TP53 DNA in patient 1 showed alteration of fragments including exon I and intron I, and, in both patients, a specific loss of TP53 DNA. In patient 2, PCR direct sequencing showed in exon VII a 9 bp deletion including codons 252-254. In patient 1, TP53 RNA and protein were not found, indicating that the unusual 5' rearrangement has affected TP53 gene expression. By contrast, patient 2 exhibited detectable TP53 RNA and protein. Detectable but weak BCL-1/PRAD1 RNA was present in both patients, whereas C-MYC RNA expression was clearly present only in case 1. The presence of TP53 hemizygous mutations in both patients suggests that TP53 abnormalities may be important in the pathogenesis of prolymphocytic leukemia (PLL), and may possibly account for the frequent resistance to therapy observed in this disease.

Morphologic, immunologic, cytogenetic, and clinical features were studied in 9 cases of acute undifferentiated leukemia (AUL). These patients were unclassifiable by FAB criteria, they were CD34+ and did not express myeloid- or lymphoid-associated antigens (CD13, CD33, CD14, CD15, CD61, CD19, CD10, CD22, CD7, CD2, CD5, CD3). Clonal abnormalities were seen in 8 of 9 cases. Del(5q) as the sole anomaly was observed in 3 cases; +13 was the primary change in 3 cases, and isolated trisomy 12 was found in 1 patient. A complex karyotype with trisomy 12q, in association with del 17p and trisomy 21q was detected in 1 case. One patient with 5q- relapsed with refractory anemia with excess of blasts; the presence of dysgranulopoiesis and a few blasts with possible monocytoid morphology in the remaining 2 patients point to a "myeloid nature" of these leukemias. Analysis of cytologic features in our 3 patients with +13, in combination with previously reported cases, suggests the occurrence of immature stem cell involvement with limited differentiation potential, possibly more along the myeloid than the lymphoid lineage. The significance of trisomy 12q in this subset of leukemia remains elusive; some clues of minimal differentiation towards the myeloid lineage in our cases are provided by positivity for the CD117 (c-kit) antigen and by relapse with acute myeloid leukemia without maturation (M1) in one patient. We conclude that, with presently available diagnostic techniques, AUL is a rare subset of leukemia, in which cytogenetic changes are confined to a few chromosomes, with prevalent involvement of 5q and of chromosomes 13 and 12. Chromosome findings may be of value in clinical practice, especially in those cases with "myeloid-oriented" karyotype.

We have analyzed genomic DNAs from a patient who developed acute myeloid leukemia 1 year after a myeloproliferative disorder was diagnosed. The development of the acute leukemia was associated with the acquisition of a t(9;11)(p22;q23) chromosome translocation. ALL-1 gene rearrangement, on chromosome 11, was present at the onset of the acute phase, but not during the chronic phase of the myeloproliferative disorder. The genomic rearrangement on chromosome 9 was within an unidentified region. By the use of polymerase chain reaction, we were able to determine that the chromosomal rearrangement was completely absent during the chronic phase of the myeloproliferative disorder, indicating that the ALL-1 gene rearrangement was causally related to the development of the acute phase. The rapid progression into the acute phase suggests that this case might be therapy related. This work provides a clear example of association of a molecular defect with the development of a specific clinical leukemic stage, and supports the indication that ALL-1 gene rearrangement is associated with poor clinical outcome in adult leukemias.

To study the cytologic profile and lineage involvement in acute myeloid leukemia (AML) with trisomy 11, cytologic, cytogenetic, and interphase cytogenetic studies were performed at presentation in two cases of acute myelomonocytic leukemia (AML-M4). Patient 1 had +11 as the sole chromosome aberration in 16/20 karyotypes whereas two related clones with +11 in all abnormal metaphases (14/18) were detected in patient 2. A proportion of interphase cells with three signals, comparable to the proportion of abnormal metaphases, was detected by fluorescent in situ hybridization (FISH) in these patients. Morphologic aberrations of the nonblast cell population affecting multiple cell lineages, along with a circulating minor megakaryoblastic component, were observed at diagnosis in both patients. By separation of bone marrow cells over a density gradient of Percoll two cell fractions were obtained, the former containing more than 80% erythroid precursors (collected at a density of 1065-1075 mg/ml), the latter containing more than 78% blast cells plus granulomonocytic precursors (collected at a density of 1060-1055 mg/ml). FISH documented the presence of a majority of interphase nuclei with three signals in the erythroblast-enriched cell fraction and in the blast-enriched cell fraction. It is concluded that cytologic features, as well as interphase cytogenetic findings on enriched cell fractions, suggest the occurrence of multipotent stem cell involvement in AML-M4 with +11.

We report a new case of Ph positive chronic myeloid leukemia (CML) without the classical rearrangement in Mbcr. By Southern blot analysis the molecular breakpoint was mapped 3 to 8 kb upstream of Mbcr. This region has not been shown to be rearranged in any other described case of CML. We did not detect any specific abnormal BCR-ABL transcript even with the use of the very sensitive RNA-PCR technique.

Clinicopathologic features of a case of lymphoblastic lymphoma (LyL) with the classic 14;18 translocation are described in this article. The patient had prominent splenomegaly with numerous splenic nodules, exhibiting a homogeneous blast cell infiltrate and occasional cells with cleft nuclei, a picture suggestive of high-grade non-Hodgkin lymphoma (NHL) possibly lymphoblastic. Early B-cell features were detected immunologically, thus confirming the diagnosis of LyL. The presence of primary splenic involvement and of the t(14;18)(q32;q21) are unusual in this histologic subset of B-cell NHL, these cytogenetic and clinicopathologic characteristics being typically associated with low- or intermediate-grade NHL of follicle center origin. These features, along with the presence of some centrocytelike cells in the biopsy sections, suggest that an unusual pattern of histologic evolution from a follicle center cell NHL may have occurred in this case of LyL.

The cytogenetic features and the proliferative and differentiation capabilities of blast cell fractions purified on a density gradient were studied in one patient with chronic myeloid leukemia (CML) in blast crisis, both at the emergence and at relapse of the disease. The results show that relapse was due to the appearance of a new leukemic cell line that was characterized by peculiar chromosomal, growth, and differentiation features, which seemingly accounted for early refractoriness to therapy and disease progression.

Cytogenetic studies were performed on the cells of bone marrow, peripheral blood, and skin tumor biopsies from a patient with mycosis fungoides at an early stage. Chromosome abnormalities were detected in 100% of the cells harvested from the cutaneous specimen, whereas the cells of the bone marrow and blood were karyotypically normal. Three related clones, showing increasing cytogenetic complexity, were found. Chromosome #12 was abnormal in all metaphases, and an abnormal 14q chromosome was present in a minority of cells belonging to the most complex emerging subclone. These data, along with the findings of important signs of chromosome imbalance, suggest a polyphasic evolution of this chronic T lymphoproliferative disease.

Eighty-nine patients who developed a secondary hematologic disorder and were studied with chromosome analysis were collected from nine institutions. The results of the study confirmed previous findings, in particular, -5/5q-, -7/7q-, -17, and +21 were the most frequently encountered aberrations. Moreover, a t(1;7)(p11;p11) was reported in four cases and consistent chromosome abnormalities were observed in a small group of patients who had been treated only with surgery, but not with chemo- or radiotherapy for a previous tumor.

A case of Ph-positive chronic myelogenous leukemia in blastic crisis was studied extensively by means of cytogenetic techniques. Karyotypic features, as well as growth patterns, kinetic data, and rates of sister chromatid exchange, were examined in bone marrow, blood, and pleural effusion cells. The data provide strong evidence for a multistep pathogenesis of the disease, the development of which appears to be linked to mechanisms of clonal selection and genetic imbalance in the malignant cell population.

Karyotypes of different cellular populations made after separation of bone marrow cells on a gradient of Percoll were evaluated in seven patients affected by chronic myelomonocytic leukemia diagnosed according to FAB criteria. Megakaryocytes, monocytic cells, and granulocytic and erythroid precursors were preferentially collected after centrifugation between density layers of 1045-1050 mg/ml, 1050-1060 mg/ml, and 1065-1070 mg/ml, respectively. The enriched cell fractions were cultured separately and submitted to cytogenetic investigation after short-term culture. Some chromosome aberrations (5q-,+8) were observed in all cellular fractions in three patients, thus providing cytogenetic evidence of the involvement of a common progenitor stem cell in this myelodysplastic disorder. On the other hand, chromosome abnormalities such as del(3)(q21) and del(11)(q23) appeared to be confined to the megakaryocytic and the monocytic fractions, respectively, in two patients. It is conceivable that lineage-restricted aberrations may develop as a consequence of a multistep clonal evolution and may show a close relationship with the hemopoietic differentiative processes.

Sixteen patients with paroxysmal nocturnal hemoglobinuria (PNH) from five European centers have been submitted to chromosome analysis. All of them had a normal bone marrow karyotype. The associations between some chromosomally abnormal cases reported in the literature and "typical" PNH or PNH phenomenon during the course of other hematological disorders are discussed.

Blood lymphocytes from 23 patients with B-cell chronic lymphocytic leukemia were stimulated with different mitogens (lipopolysaccharide from E coli, phorbol myristate acetate ester, Staphylococcus aureus, and phytohemagglutinin M form). Functional properties of stimulated cells (blastic transformation, mitotic index, cIg production, Ig secretion, and acid phosphatase positivity) were evaluated and correlated with the stage of disease and chromosomal findings. Early stages of the disease are characterized by a relatively homogeneous response to polyclonal B-cell and activators and by a restricted number of chromosomal aberrations. Advanced stages show a more heterogeneous pattern of response and a higher incidence of abnormal karyotypes suggesting an involvement of various subclonal lines.