Diane C. Louie

Ifosfamide, carboplatin, and etoposide: a highly effective cytoreduction and peripheral-blood progenitor-cell mobilization regimen for transplant-eligible patients with non-Hodgkin's lymphoma.

PURPOSE To evaluate a chemotherapy regimen that consisted of ifosfamide administered as an infusion with bolus carboplatin, and etoposide (ICE) supported by granulocyte colony-stimulating factor (G-CSF) for cytoreduction and stem-cell mobilization in transplant-eligible patients with primary refractory or relapsed non-Hodgkins lymphoma (NHL). PATIENTS AND METHODS One hundred sixty-three transplant-eligible patients with relapsed or primary refractory NHL were treated from October 1993 to December 1997 with ICE chemotherapy at Memorial Sloan-Kettering Cancer Center. Administration of three cycles of ICE chemotherapy was planned at 2-week intervals. Peripheral-blood progenitor cells were collected after cycle 3, and all patients who achieved a partial response (PR) or complete response (CR) to ICE chemotherapy were eligible to proceed to transplantation. Event-free and overall survival, ICE-related toxicity, and the number of CD34(+) cells collected after treatment with ICE and G-CSF were evaluated. RESULTS All 163 patients were assessable for response, and there was no treatment-related mortality. A major response (CR/PR) was evident in 108 patients (66.3%); 89% of the responding patients underwent successful transplantation. Patient who underwent transplantation and achieved a CR to ICE had a superior overall survival to that of patients who achieved a PR (65% v 30%; P =.003). The median number of CD34(+) cells/kg collected was 8.4 x 10(6). The dose-limiting toxicity of ICE was hematologic, with 29.4% of patients developing grade 3/4 thrombocytopenia. There were minimal nonhematologic side effects. CONCLUSION ICE chemotherapy, with ifosfamide administered as a 24-hour infusion to decrease CNS side effects, and the substitution of carboplatin for cisplatin to minimize nephrotoxicity, is a very effective cytoreduction and mobilization regimen in patients with NHL. Furthermore, the quality of the clinical response to ICE predicts for posttransplant outcome.

Blastic natural killer cell leukemia/lymphoma: A clinicopathologic study

The classification of natural killer (NK)-cell and NK-like T-cell malignancies has undergone significant evolution in recent years. Although examples of NK-cell tumors resembling acute leukemia have been described anecdotally as blastic, blastoid, or monomorphic NK-cell leukemia/lymphoma (NKL/L), the clinical and pathologic features of these tumors have not been systematically defined. We report four patients with blastic NKL/L and describe the clinical, pathologic, and immunophenotypic findings in these cases. All patients were elderly (58-82 years) and presented with cutaneous plaques. Two patients also had adenopathy, and three patients had marrow involvement at presentation. Biopsy of cutaneous lesions showed atypical superficial and deep dermal lymphoid infiltrates. Involved lymph nodes were architecturally effaced by an interfollicular infiltrate with blastic cytologic features. In Wright-Giemsa-stained blood or marrow smears, tumor cells had finely distributed nuclear chromatin, many with nucleoli, and variable amounts of cytoplasm. In contrast to many NK and NK-like T-cell disorders, azurophilic cytoplasmic granules were absent or inconspicuous. The tumor cells were immunophenotypically distinctive. They expressed intermediate density CD45, as is characteristic of blasts; in addition, the cells were positive for HLA-DR, CD2, CD4, and the NK-associated antigen CD56. Surface CD3, cytoplasmic CD3, and CD5 were negative in all cases tested, whereas CD7 was expressed in two cases. In formalin-fixed tissue, tumor cells marked with antibodies to CD43, but not with other T- or B-lineage-related antibodies. All three cases studied for Epstein-Barr viral RNA by in situ hybridization were negative. Although treatments varied, all three patients with clinical follow-up died within months of the diagnosis. The clinical course in two patients culminated in an overtly leukemic phase. These findings suggest that blastic NKL/L represents a distinct clinicopathologic entity, characterized by cutaneous, nodal, and marrow involvement by blastic cells with immunophenotypic characteristics of true NK cells. The disease afflicts elderly patients, pursues an aggressive course, and may culminate in overt leukemia.

Cytogenetic analysis of 363 consecutively ascertained diffuse large B-cell lymphomas.

Cytogenetic analysis was performed on 363 biopsy specimens with histologically confirmed diffuse large B‐cell lymphoma (DLBCL), consecutively ascertained at the Memorial Sloan‐Kettering Cancer Center, New York, between 1984 and 1994. Among 248 samples successfully karyotyped, clonal chromosomal abnormalities were noted in 215 (87%). The salient cytogenetic features of DLBCL from this analysis comprised the following. Breakpoints clustered, in decreasing frequency, at 10 recurring sites: 14q32, 18q21, 1q21, 3q27, 1p36, 8q24, 3p21, 6q21, 1p22, and 22q11. Of these, deletion breaks affecting bands 3p21 and 1p22 and translocation breaks affecting bands 14q32, 3q27, and 1q21 were frequent and distinctive for this subset of lymphomas. Translocations affecting band 14q32 were noted in 110 cases (51%) of which 42 (20%) had t(14;18)(q32;q21), 21 (10%) had t(8;14)(q24;q32) or t(8;22)(q24;q11), 14 (6.5%) had t(3;14)(q27;q32) or t(3;22)(q27;q11), and 33 (15%) had other rearrangements of 14q32. Among 144 new translocations detected in the entire group, the breakpoints in 19 were recurrent and clustered at three sites: 1q21, 3q27, and 14q32. Regions of common cytogenetic deletions were identified at 11 sites, 1p36, 1p33–34, 1p31, 1q32, 3p25–26, 3p21, 3q21, 6q15, 6q21, 6q23–24, and 7q32, suggesting possible loss of candidate tumor suppressor genes associated with DLBCL development. Of these, only those at 6q21, 6q23, and 7q32 have previously been described in lymphoid neoplasms. The group of DLBCL with translocations affecting band 14q32 showed a significantly different pattern of additional cytogenetic changes compared to the group lacking such translocation. This new comprehensive cytogenetic characterization provides the basis for investigations aimed at identifying molecular mechanisms as well as the clinical impact of cytogenetic changes in DLBCL. Genes Chromosomes Cancer 25:123–133, 1999.

Similar patterns of genomic alterations characterize primary mediastinal large-B-cell lymphoma and diffuse large-B-cell lymphoma.

To address the possible genetic relationship between primary mediastinal large‐B‐cell lymphoma (PMLBCL) and diffuse large‐B‐cell lymphoma (DLBCL), we compared DNA copy number changes identified by comparative genomic hybridization (CGH) analysis of 40 PMLBCL and 91 DLBCL tumors. We assessed their karyotypes by G‐banding; amplification of MYC, BCL2, and REL genes by Southern blotting; and incidence of nonpolymorphic BCL6 mutations by single‐strand conformation polymorphism analysis (SSCP). Overall, CGH identified overlapping and nonoverlapping patterns of DNA copy number changes in the two groups. Among the latter changes, gains of chromosomes 8, 11, 15, and 16 and losses of chromosomes 5, 10, 15, 16, 17, and 20 were seen only in DLBCL, and gains of chromosomes 10, 21, and 22 and losses of chromosomes 11, 13, and 18 were seen only in PMLBCL. Several overlapping changes were identified in both groups, with variation in incidence. Statistical analysis of these changes showed significant gains of chromosomes 3 (P ≤ 0.05) and 7q (P ≤ 0.05) in DLBCL and gains of chromosomes 9 (P ≤ 0.05) and 19 (P ≤ 0.05) and the X chromosome (P ≤ 0.05) and loss of chromosome 4 (P ≤ 0.05) in PMLBCL. Frequent recurring DNA amplification at 2p13‐15 and less frequent amplification at 6p21, 12q13, and 18q21 were noted in both groups. Recurring amplification at 1q21 was seen only in DLBCL, whereas nonrecurring amplification at 10p11.2 and 15q22‐24 was seen only in PMLBCL. G‐banded karyotype analysis identified t(3;14)(q27;q32) in one and t(14;18)(q32;q21) in two cases of PMLBCL. Seven of 13 cases exhibited SSCP variants in the 5′ noncoding region of BCL6. In addition, 19 of 24 PMLBCLs assayed for BCL6 protein expression by immunohistochemistry showed positive results, indicating an origin from a germinal center (GC)–derived B cell. Based on these data, we conclude that PMLBCL is a distinct entity among GC‐derived high‐grade DLBCLs.

Involvement of BCL6 in chromosomal aberrations affecting band 3q27 in B‐cell non‐Hodgkin lymphoma

Chromosomal band 3q27 exhibits recurring and nonrecurring translocations and other rearrangements in approximately 8% of B‐cell non‐Hodgkin lymphomas (NHL) belonging to low‐grade as well as diffuse aggressive histologies. The BCL6 gene, which encodes a zinc‐finger transcription repressor protein and which maps to chromosomal band 3q27, is deregulated in t(3;14)(q27;q32) and other translocations by substitution of its transcription regulatory sequences by those of genes on the partner chromosomes. To delineate the cytogenetics and investigate the nature and consequence of BCL6 involvement in the spectrum of 3q27 aberrations seen in NHL, we analyzed a panel of 53 NHL tumors with 3q27 aberrations for BCL6 gene rearrangements and a subset of 32 of these for mutations. We identified four new recurring translocations involving 3q27, in addition to the previously recognized t(3;14)(q27;q32) and its variant, t(3;22)(q27;q11). Histologically, the 3q27 breaks were represented by 4% mantle cell lymphomas, 38% follicular center cell lymphomas, and 58% diffuse large B‐cell lymphomas. Approximately 50% of the tumors exhibited BCL6 rearrangements, whereas 87.5% showed mutations in the 5′ noncoding region which contains the transcription regulatory sequences. These results demonstrate that a substantial proportion of cytogenetically detected 3q27 breaks in NHLs do not represent BCL6‐associated translocations. They also suggest alternate breakpoints which may lead to BCL6 deregulation, or involvement of other genes in 3q27 translocations. The frequent BCL6 mutation in these tumors is consistent with our previous observation of hypermutation of the 5′ noncoding region of the gene in lymphomas arising in the germinal‐center B‐cells. Genes Chromosomes Cancer 23:323–327, 1998.

Chromosome 18 breakpoint in t(11;18)(q21;q21) translocation associated with MALT lymphoma is proximal to BCL2 and distal to DCC.

The t(11;18)(q21;q21) translocation has recently been identified as a recurring chromosomal abnormality in a subset of extranodal marginal zone B‐cell lymphoma, a low‐grade lymphoma of mucosa‐associated lymphoid tissue (MALT). Neither the 11q21 nor the 18q21 breakpoints have been characterized by molecular genetic analysis. As a prelude to isolation of the gene(s) involved in this translocation, we have mapped the 18q21 breakpoint region by fluorescence in situ hybridization (FISH) of YAC and PAC clones. We mapped 37 YACs assigned to a 29‐cM region within the chromosomal band 18q21. Using nine of these YACs in single‐ and/or dual‐color FISH to analyze three cases of MALT lymphomas with the t(11;18)(q21;q21) translocation, we localized the breakpoints within a 1.6‐Mb nonchimeric YAC (938E1). This YAC is useful for the detection of the translocation in metaphase and in interphase cells. A nonchimeric YAC contig of an 8‐cM region around the breakpoint comprising nine YACs and a PAC contig of YAC 938E1 were constructed, which enabled the refinement of the breakpoint region in the proximal region of the YAC within a <820‐kb segment. This breakpoint is proximal to the BCL2 locus and distal to DCC and DPC4 loci in chromosomal band 18q21. Genes Chromosomes Cancer 24:156–159, 1999.

Bcl6 Gene Rearrangement and Other Cytogenetic Abnormalities in Diffuse Large Cell Lymphoma

Evidence for rearrangement of the BCL6 gene at 3q27 has been documented in 20-30% diffuse lymphomas with a large cell component (DLLC), and was found to be of prognostic significance at the time of diagnosis. To incorporate these observations into current cytogenetic and clinical prognostic models, 76 cases of DLLC with known BCL6 status were analyzed. Cytogenetic indicators of progression, including trisomy 7, trisomy 12, del(6)(q21q25), and structural alterations of 17p were less frequent in BCL6 rearranged DLLC compared to BCL6 germline tumors. Despite a 93% overall survival at median follow-up of 30 months, a trend for continued relapse resulted in a projected freedom from progression for the BCL6 rearranged cohort of 66% at 4 years, compared to 39% for the BCL6 germline cohort. Six cases among the BCL6 rearranged group lacked additional cytogenetic indicators of progression and remained free of disease at follow-up in excess of 7 years, whereas BCL6 rearranged cases with increasing numbers of cytogenetic aberrations showed decreased intervals free from progression of disease. These results suggest that BCL6 rearrangement should be combined with other known clinical and cytogenetic indicators in prognostic analyses of patients with DLLC.

Nonsyntenic Amplification of MYC with CDK4 and MDM2 in a Malignant Mixed Tumor of Salivary Gland

Karyotypic analysis of a metastatic malignant mixed tumor of the salivary gland revealed the presence of double minute chromosomes (dmin), indicative of gene amplification. Comparative genomic hybridization analysis of DNA extracted from the primary and a renal metastasis indicated overt amplification of DNA sequences derived from 8q23-24 and 12q13-15 regions. Subsequent Southern blot analysis of tumor DNA from the metastasis with the use of probes previously mapped to those regions indicated amplification of MYC at 8q23-24 and CDK4 and MDM2 at 12q13-15. Fluorescence in situ hybridization of differentially labeled MYC and MDM2 genes hybridized to tumor metaphase chromosomes revealed an independent nonsyntenic amplification of MYC and MDM2 on dmin in this tumor.

The t(2;3)(q21;q27) translocation in non-hodgkin's lymphoma displays BCL6 mutations in the 5' regulatory region and chromosomal breakpoints distant from the gene

The BCL6 gene, mapped at the chromosomal band 3q27, encodes a POZ/Zinc finger transcription repressor protein. It is frequently activated in Non-Hodgkins lymphomas (NHL) by translocations with breakpoints clustering in the 5′ major breakpoint region (MBR) as well as by mutations in the same region. The translocations lead to BCL6 activation by substitution of promoters of rearranging genes derived from the reciprocal chromosomal partners such as IG. We report the molecular genetic analysis of a novel t(2;3)(q21;q27) translocation subset in NHL comprising three cases without apparent BCL6 involvement in the translocation. Southern blot analysis of tumor DNAs utilizing BCL6 MBR probes revealed no rearrangement in two cases. Two rearranged bands in the third case resulted from a deletion in one allele and a mutation in the other allele. Southern blot analysis of DNA from one of the two tumors without BCL6 rearrangement, using a probe derived from the recently identified alternative breakpoint region (ABR), showed a rearrangement. The ABR is located 200–270 kb telomeric to MBR. Mutations were identified in the previously reported hypermutable region of BCL6 in all three tumors. In one, the mutant allele alone was found to be expressed by RT–PCR analysis of RNA. These results demonstrate the presence of 3q27 translocation breakpoints at a distance from BCL6 suggesting distant breaks that deregulate the gene or involvement of other genes that may be subject to rearrangement.

Cyclin D1 and retinoblastoma protein expression in Kaposi's sarcoma

Cyclins are implicated in the induction and control of the cell cycle. Cyclin D1 regulates G1‐phase progression by phosphorylation of the retinoblastoma protein (pRb). The Kaposis sarcoma‐associated herpesvirus/human herpesvirus 8 (KSHV) contains and transcribes an open reading frame with sequence similarities to cellular D‐type cyclins. The KSHV‐cyclin protein is associated with kinase activity capable of phosphorylating pRb in vitro. Here, we study for the first time the endogenous cyclin Dl and Rb protein expression in Kaposis sarcoma (KS) tissue. Twenty‐four consecutive biopsies of AIDS‐related (n=21) and classical (n=3) KS were studied by immunohistochemistry with monoclonal antibodies against cyclin Dl and pRb. We detected cyclin Dl in 1 of 13 patch/plaque stage, in 4 of 5 nodular stage and in 3 of 6 visceral KS lesions. By Western blot analysis, this cellular cyclin Dl monoclonal antibody did not cross‐react with the purified KSHV‐cyclin protein. The pRb was consistently detected in 24 of 24 KS lesions. In summary, early KS lesions rarely have detectable expression of endogenous cyclin Dl. Advanced and disseminated KS lesions tend to have overexpression of endogenous cyclin Dl. Therefore, cellular cyclin Dl expression appears to correlate with tumor progression in KS. The endogenous cyclin Dl is antigenically distinct from the KSHV‐cyclin homolog. The pRb, which may serve as a substrate for KSHV‐cyclin, is found in all KS lesions examined.