Activated STING in a vascular and pulmonary syndrome.

BACKGROUND: The study of autoinflammatory diseases has uncovered mechanisms underlying cytokine dysregulation and inflammation. METHODS: We analyzed the DNA of an index patient with early-onset systemic inflammation, cutaneous vasculopathy, and pulmonary inflammation. We sequenced a candidate gene, TMEM173, encoding the stimulator of interferon genes (STING), in this patient and in five unrelated children with similar clinical phenotypes. Four children were evaluated clinically and immunologically. With the STING ligand cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), we stimulated peripheral-blood mononuclear cells and fibroblasts from patients and controls, as well as commercially obtained endothelial cells, and then assayed transcription of IFNB1, the gene encoding interferon-ß, in the stimulated cells. We analyzed IFNB1 reporter levels in HEK293T cells cotransfected with mutant or nonmutant STING constructs. Mutant STING leads to increased phosphorylation of signal transducer and activator of transcription 1 (STAT1), so we tested the effect of Janus kinase (JAK) inhibitors on STAT1 phosphorylation in lymphocytes from the affected children and controls. RESULTS: We identified three mutations in exon 5 of TMEM173 in the six patients. Elevated transcription of IFNB1 and other gene targets of STING in peripheral-blood mononuclear cells from the patients indicated constitutive activation of the pathway that cannot be further up-regulated with stimulation. On stimulation with cGAMP, fibroblasts from the patients showed increased transcription of IFNB1 but not of the genes encoding interleukin-1 (IL1), interleukin-6 (IL6), or tumor necrosis factor (TNF). HEK293T cells transfected with mutant constructs show elevated IFNB1 reporter levels. STING is expressed in endothelial cells, and exposure of these cells to cGAMP resulted in endothelial activation and apoptosis. Constitutive up-regulation of phosphorylated STAT1 in patients' lymphocytes was reduced by JAK inhibitors. CONCLUSIONS: STING-associated vasculopathy with onset in infancy (SAVI) is an autoinflammatory disease caused by gain-of-function mutations in TMEM173. (Funded by the Intramural Research Program of the National Institute of Arthritis and Musculoskeletal and Skin Diseases; ClinicalTrials.gov number, NCT00059748.).

Modulation of tumor eIF4E by antisense inhibition: A phase I/II translational clinical trial of ISIS 183750-an antisense oligonucleotide against eIF4E-in combination with irinotecan in solid tumors and irinotecan-refractory colorectal cancer.

The eukaryotic translation initiation factor 4E (eIF4E) is a potent oncogene that is found to be dysregulated in 30% of human cancer, including colorectal carcinogenesis (CRC). ISIS 183750 is a second-generation antisense oligonucleotide (ASO) designed to inhibit the production of the eIF4E protein. In preclinical studies we found that EIF4e ASOs reduced expression of EIF4e mRNA and inhibited proliferation of colorectal carcinoma cells. An additive antiproliferative effect was observed in combination with irinotecan. We then performed a clinical trial evaluating this combination in patients with refractory cancer. No dose-limiting toxicities were seen but based on pharmacokinetic data and tolerability the dose of irinotecan was reduced to 160 mg/m(2) biweekly. Efficacy was evaluated in 15 patients with irinotecan-refractory colorectal cancer. The median time of disease control was 22.1 weeks. After ISIS 183750 treatment, peripheral blood levels of eIF4E mRNA were decreased in 13 of 19 patients. Matched pre- and posttreatment tumor biopsies showed decreased eIF4E mRNA levels in five of nine patients. In tumor tissue, the intracellular and stromal presence of ISIS 183750 was detected by IHC in all biopsied patients. Although there were no objective responses stable disease was seen in seven of 15 (47%) patients who were progressing before study entry, six of whom were stable at the time of the week 16 CT scan. We were also able to confirm through mandatory pre- and posttherapy tumor biopsies penetration of the ASO into the site of metastasis.

Selumetinib with and without erlotinib in KRAS mutant and KRAS wild-type advanced nonsmall-cell lung cancer.

BACKGROUND: KRAS mutations in NSCLC are associated with a lack of response to epidermal growth factor receptor inhibitors. Selumetinib (AZD6244; ARRY-142886) is an oral selective MEK kinase inhibitor of the Ras/Raf/MEK/ERK pathway. PATIENTS AND METHODS: Advanced nonsmall-cell lung cancer (NSCLC) patients failing one to two prior regimens underwent KRAS profiling. KRAS wild-type patients were randomized to erlotinib (150 mg daily) or a combination of selumetinib (150 mg daily) with erlotinib (100 mg daily). KRAS mutant patients were randomized to selumetinib (75 mg b.i.d.) or the combination. The primary end points were progression-free survival (PFS) for the KRAS wild-type cohort and objective response rate (ORR) for the KRAS mutant cohort. Biomarker studies of ERK phosphorylation and immune subsets were carried out. RESULTS: From March 2010 to May 2013, 89 patients were screened; 41 KRAS mutant and 38 KRAS wild-type patients were enrolled. Median PFS in the KRAS wild-type arm was 2.4 months [95% confidence interval (CI) 1.3-3.7] for erlotinib alone and 2.1 months (95% CI 1.8-5.1) for the combination. The ORR in the KRAS mutant group was 0% (95% CI 0.0% to 33.6%) for selumetinib alone and 10% (95% CI 2.1% to 26.3%) for the combination. Combination therapy resulted in increased toxicities, requiring dose reductions (56%) and discontinuation (8%). Programmed cell death-1 expression on regulatory T cells (Tregs), Tim-3 on CD8+ T cells and Th17 levels were associated with PFS and overall survival in patients receiving selumetinib. CONCLUSIONS: This study failed to show improvement in ORR or PFS with combination therapy of selumetinib and erlotinib over monotherapy in KRAS mutant and KRAS wild-type advanced NSCLC. The association of immune subsets and immune checkpoint receptor expression with selumetinib may warrant further studies.

Helper virus induced T cell lymphoma in nonhuman primates after retroviral mediated gene transfer.

Moloney Murine Leukemia Virus (MoMuLV) causes T cell neoplasms in rodents but is not known to be a pathogen in primates. The core protein and enzyme genes of the MoMuLV genome together with an amphotropic envelope gene are utilized to engineer the cell lines that generate retroviral vectors for use in current human gene therapy applications. We developed a producer clone that generates a very high concentration of retroviral vector particles to optimize conditions for gene insertion into pluripotent hematopoietic stem cells. This producer cell line also generates a much lower concentration of replication-competent virus that arose through recombination. Stem cells from rhesus monkeys were purified by immunoselection with an anti-CD34 antibody, incubated in vitro for 80-86 h in the presence of retroviral vector particles with accompanying replication-competent virus and used to reconstitute recipients whose bone marrow had been ablated by total body irradiation. The retroviral vector genome was detected in circulating cells of five of eight transplant recipients of CD34+ cells and in the circulating cells of two recipients of infected, unfractionated bone marrow mononuclear cells. Three recipients of CD34+ cells had a productive infection with replication-competent virus. Six or seven mo after transplantation, each of these animals developed a rapidly progressive T cell neoplasm involving the thymus, lymph nodes, liver, spleen, and bone marrow. Lymphoma cells contained 10-50 copies of the replication-competent virus, but lacked the retroviral vector genome. We conclude that replication-competent viruses arising from producer cells making retroviral vectors can be pathogenic in primates, which underscores the importance of carefully screening retroviral producer clones used in human trials to exclude contamination with replication-competent virus.

Amelanotic melanoma in a New Zealand White Rabbit (Oryctolagus cuniculus).

A 3.5-year-old intact male double-transgenic New Zealand white rabbit (Oryctolagus cuniculus), apoA-I and LCAT (apolipoprotein and lecithin:cholesterol acyltransferase), was presented with a discrete, raised facial mass (0.5 x 1.0 x 1.0 cm). The mass was surgically excised, with reoccurrence to the same site 88 days later. A second surgical excision was performed, and the rabbit died 3 weeks later from respiratory distress. At necropsy, multiple varying-sized masses were observed in the ventral mandibular region and throughout the lungs, pleura, and diaphragm. On histopathology, the masses were composed of moderately anisocytotic and anisokaryotic polygonal to spindloid cells with moderate finely granular, lightly eosinophilic cytoplasm, having round to oval nuclei with one to several nucleoli and finely stippled chromatin. Mitotic figures were frequent. Lymphatic and venous invasion were noted with neoplastic cells metastasized to the submandibular lymph nodes, lungs, liver, and adventitial surface of the aorta. Fontana-Masson stain was negative for melanin, thereby necessitating immunohistochemistry and transmission electron microscopy. Positive staining with MART-1 (a melanocyte protein marker) combined with transmission electron microscopy revealing type II melanosomes confirmed the diagnosis of an amelanotic melanoma.

Protracted haemangioblastic proliferation and differentiation in von Hippel-Lindau disease.

Von Hippel-Lindau (VHL) disease is caused by germline mutation of the VHL tumour suppressor gene. Patients frequently develop multiple nervous system tumours, denominated haemangioblastomas. Analysis of affected autopsy tissues suggests that tumourigenesis propagates from developmentally arrested, embryonic cells and progresses with consistent architectural, cytological, and molecular sequences similar to haemangioblastic formation and differentiation in the embryo. In this study, we analysed 156 nervous system tumours, 139 of which had been surgically resected from 83 VHL patients. We demonstrate that large tumours consistently contain epithelioid components characteristic of haemangioblastic differentiation in comparison to small tumours that solely display a poorly differentiated, mesenchymal structure. We further show exclusive activation of HIF2alpha in both small mesenchymal tumours and the mesenchymal component of large tumours, whereas activation of HIF1alpha is associated with epithelioid structure. We also show that the MIB1 proliferative index is variably increased in the epithelioid component of large tumours, with extramedullary haematopoiesis foci within the epithelioid component at 100%. These data provide compelling evidence that nervous system tumourigenesis in VHL disease represents a protracted process of haemangioblastic proliferation and differentiation that parallels haemangioblastic formation and differentiation in the embryo.

Cytomegalovirus induction of tumor necrosis factor-alpha by human monocytes and mucosal macrophages.

Cytomegalovirus (CMV) is a major cause of inflammatory organ disease in immunosuppressed persons. To elucidate the mechanisms of CMV-induced inflammation, we investigated whether tumor necrosis factor-alpha (TNF-alpha) was involved in the pathogenesis of CMV colitis in patients with AIDS. In in situ hybridization experiments, TNF-alpha mRNA was shown to be abundantly present in colonic mucosa from AIDS patients with CMV colitis but not in colonic mucosa from control (AIDS and normal) subjects. The TNF-alpha transcripts, identified in macrophage-like cells containing cytomegalic inclusions, were positively associated with CMV, but not HIV-1, within the mucosa. In in vitro experiments, a patient-derived isolate of CMV, but not HIV-1Ba-L, induced human monocytes to express TNF-alpha mRNA and to release increased levels of TNF-alpha peptide following stimulation. CMV induction of TNF-alpha may play a critical role in CMV-induced inflammation and, since TNF-alpha upregulates expression of HIV-1, offers a mechanism by which CMV could serve as a co-factor for HIV-1 expression without both viruses infecting the same cell.

Block of AIDS-Kaposi's sarcoma (KS) cell growth, angiogenesis, and lesion formation in nude mice by antisense oligonucleotide targeting basic fibroblast growth factor. A novel strategy for the therapy of KS.

Kaposi's sarcoma (KS) is the most frequent tumor of HIV-1-infected individuals (AIDS-KS). Typical features of KS are proliferating spindle-shaped cells, considered to be the tumor cells of KS, and endothelial cells forming blood vessels. Basic fibroblast growth factor (bFGF), a potent angiogenic factor, is highly expressed by KS spindle cells in vivo and after injection in nude mice it induces vascular lesions closely resembling early KS in humans. Similar lesions are induced by inoculating nude mice with cultured spindle cells from AIDS-KS lesions (AIDS-KS cells) which produce and release bFGF. Here we show that phosphorothioate antisense (AS) oligonucleotides directed against bFGF mRNA (ASbFGF) inhibit both the growth of AIDS-KS cells derived from different patients and the angiogenic activity associated with these cells, including the induction of KS-like lesions in nude mice. These effects are due to the block of the production of bFGF which is required by AIDS-KS cells to enter the cell cycle and which, after release, mediates angiogenesis. The effects of ASbFGF are specific, dose dependent, achieved at low (0.1-1 microM), nontoxic, oligomer concentrations, and are reversed by the addition of bFGF to the cells, suggesting that ASbFGF oligomers are promising drug candidates for KS therapy.

Flavopiridol, a novel cyclin-dependent kinase inhibitor, suppresses the growth of head and neck squamous cell carcinomas by inducing apoptosis.

Flavopiridol (HMR 1275) has been identified recently as a novel antineoplastic agent in the primary screen conducted by the Developmental Therapeutics Program, National Cancer Institute. Flavopiridol inhibits most cyclin-dependent kinases (cdks) and displays unique anticancer properties. Here, we investigated whether this compound was effective against head and neck squamous cell carcinomas (HNSCC). Exposure of HNSCC cells to flavopiridol diminished cdc2 and cdk2 activity and potently inhibited cell proliferation (IC50 43-83 nM), which was concomitant with the appearance of cells with a sub-G1 DNA content. Moreover, DNA fragmentation and TUNEL (terminal deoxynucleotidyl transferase-mediated nick end labeling) reaction confirmed that flavopiridol induces apoptosis in all cell lines, even on certain HNSCC cells that are insensitive to apoptosis to DNA-damaging agents (gamma-irradiation and bleomycin). A tumorigenic HNSCC cell line was used to assess the effect of flavopiridol in vivo. Treatment (5 mg/kg per day, intraperitoneally) for 5 d led to the appearance of apoptotic cells in the tumor xenografts and caused a 60-70% reduction in tumor size, which was sustained over a period of 10 wk. Flavopiridol treatment also resulted in a remarkable reduction of cyclin D1 expression in HNSCC cells and tumor xenografts. Our data indicate that flavopiridol exerts antitumor activity in HNSCC, and thus it can be considered a suitable candidate drug for testing in the treatment of refractory carcinomas of the head and neck.

A link between increased transforming activity of lymphoma-derived MYC mutant alleles, their defective regulation by p107, and altered phosphorylation of the c-Myc transactivation domain.

The c-Myc protein is a transcription factor with an N-terminal transcriptional regulatory domain and C-terminal oligomerization and DNA-binding motifs. Previous studies have demonstrated that p107, a protein related to the retinoblastoma protein, binds to the c-Myc transcriptional activation domain and suppresses its activity. We sought to characterize the transforming activity and transcriptional properties of lymphoma-derived mutant MYC alleles. Alleles encoding c-Myc proteins with missense mutations in the transcriptional regulatory domain were more potent than wild-type c-Myc in transforming rodent fibroblasts. Although the mutant c-Myc proteins retained their binding to p107 in in vitro and in vivo assays, p107 failed to suppress their transcriptional activation activities. Many of the lymphoma-derived MYC alleles contain missense mutations that result in substitution for the threonine at codon 58 or affect sequences flanking this amino acid. We observed that in vivo phosphorylation of Thr-58 was absent in a lymphoma cell line with a mutant MYC allele containing a missense mutation flanking codon 58. Our in vitro studies suggest that phosphorylation of Thr-58 in wild-type c-Myc was dependent on cyclin A and required prior phosphorylation of Ser-62 by a p107-cyclin A-CDK complex. In contrast, Thr-58 remained unphosphorylated in two representative mutant c-Myc transactivation domains in vitro. Our studies suggest that missense mutations in MYC may be selected for during lymphomagenesis, because the mutant MYC proteins have altered functional interactions with p107 protein complexes and fail to be phosphorylated at Thr-58.

An overview of the classification of non-Hodgkin's lymphomas: an integration of morphological and phenotypical concepts.

An analysis of trends in the incidence of non-Hodgkin's lymphoma requires an understanding of individual disease entities within this broad group. The non-Hodgkin's lymphomas represent a diverse group of malignancies that have in common an origin from lymphoid cells. Nevertheless, these disorders are heterogeneous in their clinical behavior, morphological appearance, cellular origin, etiology, and pathogenesis. A modern classification of non-Hodgkin's lymphomas must include an integration of morphological, immunophenotypical, and molecular concepts in order to delineate individual diseases within this broad group. Existing classification schemes such as the working formulation, while they may be useful in providing a guide to clinical management, cannot provide this information in the absence of other data. This point is most readily made with the low-grade B-cell lymphomas which include follicular lymphomas, mantle cell lymphomas, small lymphocytic lymphomas, immunosecretory disorders, and lymphomas of mucosa-associated lymphoid tissues. Each of these malignancies has a distinct phenotype and genotype, and indubitably each has a different etiology. The postthymic T-cell tumors are equally diverse. Analysis of epidemiological data from cancer registries must include a recognition that our ability to recognize individual diseases from historical data is limited. Studies of trends in the non-Hodgkin's lymphomas should attempt to delineate biological markers that may be of relevance to pathogenesis in both historical and prospectively accrued cases.

Involvement of CDKN2 (p16INK4A/MTS1) and p15INK4B/MTS2 in human leukemias and lymphomas.

CDKN2 (p16INK4A/MTS1) and p15INK4B/MTS2 have been shown recently to be potent inhibitors of the cyclin D/cyclin-dependent kinase 4 complex. Both genes are candidates for the putative tumor suppressor gene located at chromosome 9p21. We examined a series of 14 hematopoietic cell lines and 117 primary lymphoid tumors for deletion and mutation of these genes. The primary tumors included 65 T-cell malignancies and 52 B-cell malignancies. The cell line study revealed 4 of 4 T-ALL lines to have homozygous deletions of CDKN2. Two of the 4 lines also showed homozygous deletions of MTS2, while the remaining 2 lines retained both MTS2 alleles. In the primary tumors, homozygous deletions of both CDKN2 and MTS2 were found in 35% of the T-ALL/lymphoblastic lymphoma (8 of 23). Homozygous deletions of both genes also occurred in 1 of 3 precursor B-ALLs. PCR-single strand conformational polymorphism analysis of CDKN2 exons 2 and 3 and MTS2 exon 2 failed to demonstrate mutations in either CDKN2 or MTS2 in any of the T- or B-cell malignancies, with two possible exceptions. These results are consistent with a role for CDKN2 and/or MTS2 in the pathogenesis of some lymphoid leukemia/lymphomas, particularly in T-ALL/lymphoblastic lymphoma.

Clonal evolution of t(14;18) follicular lymphomas demonstrated by immunoglobulin genes and the 18q21 major breakpoint region.

A 2.8-kilobase major breakpoint region on chromosome segment 18q21 is the site of most t(14;18) translocations typical of human follicular lymphomas. Breaks are focused at the 5' end of joining (JH) regions of immunoglobulin (Ig) on chromosome 14, indicating that the translocation occurs at a pre-B-cell stage during attempted heavy (H) chain joining. A new gene from 18q21 (Bcl-2) is placed in the H chain locus creating a unique, translocation-specific JH;18q21 rearrangement that presumably represents a transformation event. In addition, normal Ig gene joining occurs in a H before light (L) chain and K before lambda cascade, creating ordered clonal markers. These serial markers were examined to determine if variations in Ig gene patterns during the natural history of lymphomas represent the emergence of truly separate neoplasms or heterogeneity of a single neoplasm. We examined 45 serial biopsies from 16 B follicular lymphoma patients; six cases showed variation in Ig gene patterns over time. Seven individuals had a detectable JH;18q21 rearrangement present, and it remained unchanged over 5-10 years. Further rearrangements of H chain genes occurred on the normal chromosome 14 within evolving subclones of the original tumor. Lambda L chains also underwent additional rearrangements in two instances, while K gene patterns remained unchanged. All variations in the normal H and L chain genes were 2 degrees rearrangements occurring at a mature B-cell stage following the initial successful rearrangement of a H and L chain. In contrast the t(14;18) breakpoint was conserved in each individual, indicating that evolving neoplastic subpopulations arose from a common clonal progenitor cell.

Mutations in the coding region of c-MYC in AIDS-associated and other aggressive lymphomas.

Our previous studies of the translocated MYC gene in Burkitt's lymphoma showed the existence of clustered somatic mutations located in the transcriptional activation domain. We now report that aggressive lymphomas arising in the acquired immunodeficiency syndrome (AIDS) contain similar mutations and that the presence of mutations is correlated with the rearrangement of the oncogene. Mutations were also found in other de novo non-AIDS, non-Burkitt's aggressive lymphomas with MYC rearrangements. An unusual asparagine to serine mutation at codon 11 was identified in several transformed follicular lymphomas without MYC rearrangement but not in normal tissues from patients with this mutation. These findings indicate that AIDS-associated and other de novo aggressive lymphomas with the MYC gene rearrangement are subject to the same mutation and selection process that affects Burkitt's lymphomas.

Mechanism of bcl-2 activation in human follicular lymphoma.

The t(14; 18) chromosomal translocation of human follicular lymphoma recombines the bcl-2 gene from chromosome 18 with the immunoglobulin heavy chain joining region. In the t(14; 18) translocation bearing cell line SU-DHL-6, this results not only in an inappropriately high rate of bcl-2 transcription for a mature B cell, but also in two potentially critical point mutations. To determine the relative importance of these mutations, we searched for their presence in DNA from the involved lymph nodes of 12 patients with t(14; 18) follicular lymphoma. bcl-2 genomic sequences were specifically amplified by the polymerase chain reaction technique and then directly sequenced. None of the 12 samples analysed revealed the codon 7 or codon 129 mutation detected in SU-DHL-6. We conclude that abnormal expression of bcl-2 rather than structural alterations at codon 7 or 129 play an important role in the disordered growth and differentiation of follicular B-cell lymphoma.

Clustered mutations in the second exon of the MYC gene in sporadic Burkitt's lymphoma.

The primary tumors from 15 untreated patients with Burkitt's lymphoma were analysed for abnormalities in the coding region of the MYC gene by single stranded conformational polymorphism (SSCP) analysis followed by DNA sequencing. Fourteen of the 15 tumors had one or more clonal mutations. Forty one mutations were found in the second exon; only one occurred in the third exon. Seven tumors had mutations that clustered in a region spanning amino acids 38-63. Four of these possessed mutations that altered prolines at positions 57 (3), 60 (1), and 63 (1). Seven tumors were mutated in the central portions of the second exon. These occurred at position 95 (2), position 115 (2), position 137 (1), and position 138 (3). Analysis of the published sequences from five lymphoma cell lines and one primary tumor showed a similar clustering of mutations, with all six having mutations in codons between positions 38-63. The regions where mutations occurred have been associated with a variety of properties, including transcriptional activation and cellular transformation. The number and location of mutations showed no correlation with either chromosome 8 or chromosome 14 breakpoints or with the Epstein-Barr virus positivity of the tumors. This unexpected, frequent occurrence of clustered mutations in the second exon of the MYC gene suggests a role for the mutated MYC proteins in the pathogenesis of Burkitt's lymphoma, possibly through altered interactions of this domain with other cellular factors.

c-myc box II mutations in Burkitt's lymphoma-derived alleles reduce cell-transformation activity and lower response to broad apoptotic stimuli.

In addition to c-myc rearrangement, over 50% of Burkitt's lymphoma cases present clustered mutations in exon 2, where many of the functional activities of c-Myc protein are based. This report describes the functional consequences induced by tumour-derived c-myc mutations located in c-myc box II. Two mutated alleles were studied, focusing on the P138C mutation, and compared to wild-type c-myc. The c-Myc transformation, transactivation and apoptosis activities were explored based on cells over-expressing c-Myc. While the transcriptional activation activity was not affected, our experiments exploring the anchorage-independent growth capacity of c-Myc-transfected Rat1a cells showed that c-Myc box II mutants were less potent than wild-type c-Myc in promoting cell transformation. Considering the possibility that these mutations could be interfering with the ability of c-Myc to promote apoptosis, we tested c-Myc-transfected Rat1a fibroblasts under several conditions: serum deprivation-, staurosporine- and TNFalpha-induced cell death. Interestingly, the mutated alleles were characterized by an overall decrease in ability to mediate apoptosis. Our study indicates that point mutations located in c-Myc box II can decrease the ability of the protein to promote both transformation and apoptosis without modifying its transactivating activity.

Diffuse small noncleaved-cell, non-Burkitt's lymphoma in adults: a high-grade lymphoma responsive to ProMACE-based combination chemotherapy.

PURPOSE: To review the efficacy of cyclophosphamide, doxorubicin, etoposide, methotrexate with leucovorin, and prednisone (ProMACE)-based combination chemotherapy programs in the treatment of patients with diffuse small noncleaved-cell non-Burkitt's lymphoma. PATIENTS AND METHODS: Thirty-three patients with diffuse small noncleaved-cell non-Burkitt's lymphoma were accrued: eight with localized disease were treated with modified ProMACE-mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) plus involved-field radiation therapy, and 25 with advanced-stage disease were treated with ProMACE/MOPP flexitherapy (n = 8), ProMACE-MOPP (n = 9), or ProMACE-cytarabine, bleomycin, vincristine, and methotrexate with leucovorin (CytaBOM) (n = 8). The median follow-up duration is 10 years. RESULTS: All eight patients with localized disease achieved a complete response, none have relapsed, and one died of intercurrent illness. Among patients with advanced-stage disease, five of eight (63%) flexitherapy-treated patients, six of nine (67%) ProMACE-MOPP-treated patients, and eight of eight (100%) ProMACE-CytaBOM-treated patients achieved a complete response. If the two ProMACE-MOPP-based groups are considered together, disease-free and overall survival rates at 15 years are projected at 61% and 35%, respectively. In contrast, only one patient has relapsed from a ProMACE-CytaBOM-induced complete remission, and overall survival of ProMACE-CytaBOM-treated patients (88%) is significantly higher than that for flexitherapy and ProMACE-MOPP (P2 = .04). CONCLUSION: Adult patients with diffuse small non-cleaved-cell non-Burkitt's lymphoma may be effectively treated with regimens that are effective in other aggressive lymphomas (eg, diffuse large-cell lymphoma).

Mutation of the ras genes is a rare genetic event in the histologic transformation of follicular lymphoma.

The role of ras gene mutations in the progression of follicular lymphoma has been ascertained by SSCP-PCR and sequencing. A total of 40 transformed lymphomas were studied, 16 of which had a matched preceding low-grade biopsy. Only one transformed lymphoma was found to have a missense mutation at codon 12 of N-ras, resulting in an amino acid change of glycine to serine. We conclude that mutation within the ras gene family is a rare event in the transformation of follicular lymphoma.

Absence of p18 mutations or deletions in lymphoid malignancies.

p18 is a recently described cyclin-dependent kinase inhibitor (CDK-I) wih homology to p16 and p15. The latter two CDK-Is have been implicated as possible tumor suppressor genes in a wide variety of human tumors, including hematological malignancies. Because of p18's structural and functional homology to p16 and p15, we hypothesized that it may also function as a tumor suppressor gene in some lymphoid malignancies. To explore this possibility we examined 81 primary lymphoid tumors for deletion and mutation p18. The primary tumors included 40 T cell malignancies and 41 B cell malignancies. None of the lymphoid tumors studied possessed deletions of p18, including a group of lymphoblastic lymphomas which we previously reported to have deletions of p16 and p15. PCR-SSCP analysis of the p18 gene identified a single polymorphism of codon 114, but failed to demonstrate mutations in any of the lymphoid tumors. These results do not support a role for p18 in the pathogenesis of the lymphoid neoplasms studied.