Jorge J. Yunis

Distinctive Chromosomal Abnormalities in Histologic Subtypes of Non-Hodgkin's Lymphoma

Using a new high-resolution technique for chromosomal analysis, we have successfully studied biopsy specimens of lymph nodes from 42 of 44 patients with non-Hodgkins lymphoma and have categorized them using the new international histologic formulation and immunologic markers. Abnormalities of the clonal chromosomes were detected in all 42 patients. Three recurrent chromosomal aberrations were found to correlate with certain histologic types: a translocation between chromosomes 18 and 14 in 16 of 19 patients with follicular lymphomas (small cleaved cell, mixed cell, and large cell); a translocation between chromosomes 8 and 14 in 5 of 6 patients with small noncleaved-cell (non-Burkitts) or large-cell immunoblastic lymphoma; and a trisomy 12 in 4 of 11 patients with small-cell lymphocytic lymphoma. Our findings suggest that characteristic chromosomal defects occur in certain lymphoma subtypes and that high-resolution chromosomal analysis promises to become an important tool in improving our basic understanding of lymphoid cancers.

Multiple recurrent genomic defects in follicular lymphoma. A possible model for cancer.

Several steps in the clinical evolution of human neoplasia are associated with a variety of recurrent chromosomal defects that could prove essential to the understanding of cancer. We found 15 types of nonrandom chromosomal abnormalities in a study of 71 patients with follicular lymphoma; 10 of the types appeared to influence the histopathological findings, clinical course, or response to treatment. A translocation, t(14;18), observed in 85 percent of all patients appeared to be the main determinant of a follicular pattern. Ten patients with a t(14;18) as a single defect had the histologic features of follicular small cleaved-cell lymphoma. Most did not require treatment for one to four years, because their tumors had an initial indolent course. In contrast, patients with follicular small cleaved-cell lymphoma with t(14;18) and deletion 13q32 acquired the hematologic features of leukemia and had an acceleration of the disease. A deletion 6q together with a complete or partial trisomy 7 or trisomy 12 (or both) was associated with the clinically more aggressive follicular mixed small- and large-cell or large-cell histologic type, which often evolves from follicular small-cell lymphoma. A complete or partial trisomy 3, 18, or 21 correlated almost exclusively with follicular large-cell lymphoma. In all follicular stages, a trisomy 2 or duplication 2p often accompanied an accelerated clinical course and a poor response to treatment. This study suggests that several discrete genomic defects may govern the evolution of a patients malignant disease.

New chromosome techniques in the study of human neoplasia

Amethopterin synchronization of bone marrow and lymph node cells makes it possible to obtain well banded and elongated metaphases and prometaphases in the majority of patients with leukemia and lymphoma. Chromosomal analysis of most neoplasias is also possible through the use of mild tumor cell disaggregation methods, short term culture on feeder layers, and special media that help in the preferential proliferation of cancer cells. In the past, only about half of all patients with acute leukemia and lymphoma could be shown to have a chromosomal defect, and only a small proportion of solid tumors could be analyzed. With the new technology, abnormal tissue from the majority of cancer patients can be successfully studied and chromosomal abnormalities detected.

All Patients with Acute Nonlymphocytic Leukemia May Have a Chromosomal Defect

Previous studies of banded marrow chromosomes suggest that half the patients with acute nonlymphocytic leukemia (ANLL) have normal karyotypes. To determine whether high-resolution chromosome analysis could detect additional abnormalities, we studied marrow from 26 patients with ANLL, using methotrexate cell synchronization as well as a direct technique. In 24 patients, including 18 who were untreated, adequate mitoses were obtained. All demonstrated clonal chromosomal abnormalities, which involved a balanced translocation in 11 cases, a complete or partial monosomy in 10, and a trisomy in six. Previously reported recurring defects in ANLL were identified, including t(15;17) in two cases, -7 in two cases, and +8 in three cases. In addition, a new specific abnormality involving band 11q23 was noted in one patient with acute monocytic leukemia and in two with myelomonocytic leukemia. Our results suggest that most, if not all, patients with ANLL have chromosomal changes, and that our new technique may allow more precise identification of subtypes of ANLL with characteristic clinical and hematologic features.

bcl-2 and Other Genomic Alterations in the Prognosis of Large-Cell Lymphoma

Approximately half the patients with diffuse or follicular large-cell or mixed large- and small-cell lymphoma enter a prolonged remission or are cured after receiving combined-drug therapy. It has been unclear, however, why the other half do not respond. We evaluated 54 previously untreated patients with diffuse lymphoma and 20 with follicular lymphoma, all of whom had a large-cell component and Stage II through IV disease, subsequently treated with combined chemotherapy. Different recurrent genomic defects were associated with differences in the response to treatment. Among the 54 patients with diffuse lymphoma, all 12 patients with a duplication of chromosome 3p had a complete clinical remission after a median follow-up of 39 months (11 patients survived). In contrast, all seven patients with a duplication of chromosome 2p had a partial response or no response to treatment and a median survival of six months (all died). Among the 20 patients with follicular lymphoma, all 5 patients with duplication 3p or +3 had a complete clinical remission (all survived), and 3 of 4 patients with duplication 2p or +2 had no response or a partial response to treatment and died. Twenty-three patients with B-cell non-immunoblastic lymphoma or follicular lymphoma who had a bcl-2 oncogene rearrangement had a poorer response to therapy (7 of 23 with complete remission) than the patients without bcl-2 rearrangement (21 of 26 with complete remission). We conclude that in large-cell or mixed-cell lymphoma, duplication of chromosome 3p is associated with a relatively good prognosis and duplication of chromosome 2p or bcl-2 oncogene rearrangement is associated with a relatively poor prognosis. Because such multiple recurrent genomic defects are also common in most other types of cancer, they may have general prognostic importance.

The Characterization of High-Resolution G-Banded Chromosomes of Man

The detailed characterization of G-banding patterns of high resolution human chromosomes has been possible with the utilization of a refined cell synchronization technique which routinely yields a large number of excellent quality cells in late prophase, prometaphase, early metaphase, and mid-metaphase. These mitotic cells exhibit up to a 400% increase in the number of bands previously visualized by standard methods. From studies of the banding patterns, it has become evident that the G-positive and, to some extent, the G-negative bands of mid-metaphase results from a coalescence of finer subbands of earlier stages and that each band and its corresponding subbands maintain a constant location throughout the process of chromosome condensation. A precise schematic representation of the number, position, height and staining intensity of bands is presented for the five largest chromosomes of the complement at the four mitotic stages.

Refined chromosome study helps define prognostic subgroups in most patients with primary myelodysplastic syndrome and acute myelogenous leukaemia

Based on a 6·1/2‐year study of 284 consecutive adult patients with primary myelodysplastic syndrome (MDS) and and acute myelogenous leukaemia (AML), we have found that refined chromosome analysis can be used as an independent prognostic indicator in the great majority of patients with MDS and AML. In MDS, the FAB subtype was also found to have prognostic value and this was enhanced when the chromosomal findings were taken into consideration. In AML, the age of the patient correlated more closely with the chromosomal changes in predicting prognosis in most patients than did the FAB classification.

High-Resolution Chromosomes as an Independent Prognostic Indicator in Adult Acute Nonlymphocytic Leukemia

Using high-resolution chromosomes of bone-marrow specimens from 105 consecutive adult patients with de novo acute nonlymphocytic leukemia, we found an unusually high degree of complexity in this disorder, which may explain previous difficulties in identifying useful prognostic indicators. Specimens from 99 of the 105 patients were successfully analyzed, and 92 (93 per cent) had a chromosomal defect. Seventeen categories were identified, 12 representing a specific recurrent defect. Three of them have been found to have independent prognostic importance. Patients with an inversion 16 (9 per cent), diagnosed as having M2, M4, or M5b disease according to the morphologic classification of the French-American-British Acute Leukemia Cooperative Study Group, had a uniform and sustained complete remission and a median survival of 25 months. In contrast, 14 patients (14 per cent) with complex chromosomal abnormalities and a diagnosis of M1, M2, M4, M5a, or M6 disease had a very poor prognosis. In 12 of the 14 patients efforts to achieve induction of remission failed, and the group had a median survival of 2.5 months. A third group with a trisomy 8 as the single defect (11 per cent) had an intermediate prognosis and a median survival of 10 months. With the different types of treatment for acute nonlymphocytic leukemia that are now available, we suggest that high-resolution chromosome analysis will become an important tool in selecting specific types of therapy for groups of patients with differing prognoses.

Recurrent chromosomal defects are found in most patients with non-Hodgkin's-lymphoma

Using methotrexate cell synchronization, we successfully analyzed chromosomal preparations of 40 lymph node biopsies and one bone marrow sample from 44 patients with non-Hodgkins, non-Burkitts lymphoma. All of the 41 patients successfully analyzed showed clonal chromosomal abnormalities. In 25 of the 41 (61%), the defects were found to be consistent with (A) a deletion 6q in five of seven patients with diffuse large cell lymphoma, (B) a t(11;14), a del 11q, or a + 12 in seven of nine patients with small cell lymphocytic lymphoma, and (C) a t(14;18) in 12 of 15 patients with follicular lymphoma (small cleaved and mixed small and large cleaved) and in a single case of diffuse large cell lymphoma. In three patients with small cell lymphocytic lymphoma whose biopsies exhibited a t(11;14), lymphocytes were cultured and chromosomes examined for the presence of fragile sites. In two, frequent breaks at band 11q13.3 were observed. Such findings suggest a possible relationship between a fragile site and a predisposition to a specific chromosomal rearrangement in human neoplasia.

Localization of mouse satellite DNA in constitutive heterochromatin

Abstract Sonication of nuclei from the liver and brain of male mice yields three chromatin fractions with different sedimentation characteristics: a constitutive heterochromatin fraction which sediments at 3500 g, an intermediate chromatin fraction which sediments at 78,000 g and a euchromatin fraction which is recovered by precipitation with ethanol. Cesium chloride gradient centrifugation of DNA extracted from the three fractions revealed that the DNA from the constitutive heterochromatin is composed primarily of satellite DNA and represents in excess of 70% of the satellite DNA of the genome. The implications of this findings are discussed.