Vorasidenib and ivosidenib in IDH1-mutant low-grade glioma: a randomized, perioperative phase 1 trial

Vorasidenib and ivosidenib inhibit mutant forms of isocitrate dehydrogenase (mIDH) and have shown preliminary clinical activity against mIDH glioma. We evaluated both agents in a perioperative phase 1 trial to explore the mechanism of action in recurrent low-grade glioma (IGG) and select a molecule for phase 3 testing. Primary end-point was concentration of D-2-hydroxyglutarate (2-HG), the metabolic product of mIDH enzymes, measured in tumor tissue from 49 patients with mIDH1-R132H nonenhancing gliomas following randomized treatment with vorasidenib (50 mg or 10 mg once daily, q.d.), ivosidenib (500 mg q.d. or 250 mg twice daily) or no treatment before surgery. Tumor 2-HG concentrations were reduced by 92.6% (95% credible interval (CrI), 76.1-97.6) and 91.1% (95% CrI, 72.0-97.0) in patients treated with vorasidenib 50 mg q.d. and ivosidenib 500 mg q.d., respectively. Both agents were well tolerated and follow-up is ongoing. In exploratory analyses, 2-HG reduction was associated with increased DNA 5-hydroxymethylcytosine, reversal of 'proneural' and 'stemness' gene expression signatures, decreased tumor cell proliferation and immune cell activation. Vorasidenib, which showed brain penetrance and more consistent 2-HG suppression than ivosidenib, was advanced to phase 3 testing in patients with mIDH LGGs. Funded by Agios Pharmaceuticals, Inc. and Servier Pharmaceuticals LLC; ClinicalTrials.gov number NCT03343197.

Impact of mutant IDH (mIDH) inhibition on DNA hydroxymethylation, tumor cell function, and tumor immune microenvironment (TIME) in resected mIDH1 lower-grade glioma (LGG)

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Background: Somatic mutations in IDH1 and IDH2 occur in ̃80% and ̃4% of LGGs, respectively, promoting tumorigenesis via increased levels of the oncometabolite D-2-hydroxyglutarate (2-HG). Vorasidenib (VOR; AG-881) is an oral, brain-penetrant, dual inhibitor of mIDH1/2; ivosidenib (IVO; AG-120) is a first-in-class oral inhibitor of mIDH1. In this ongoing perioperative study, treatment with IVO/VOR reduced 2-HG levels in resected tumors vs untreated control tumors in patients (pts) with LGG (NCT03343197; Mellinghoff SNO 2019). We assessed the biological impact of 2-HG suppression on tumors and TIME. Methods: Pts (n = 49) with recurrent, non-enhancing, mIDH1-R132H LGG eligible for resection were randomized to IVO (500 mg QD/250 mg BID), VOR (10/50 mg QD), or no treatment, for 4 weeks preoperatively. Tumor tissue samples collected at surgery were assessed in genomic (n = 42), transcriptomic (n = 42), and immunohistochemistry (IHC; n = 43) analyses. Unpaired t-test was used for statistical comparisons. Results: Optimal 2-HG suppression (post-treatment 2-HG below the upper limit of 2-HG levels in a reference set of 15 wild-type [wt] IDH samples) was observed in 23 of 40 pts, including 9 (90%) pts receiving VOR 50 mg QD and 6 (50%) receiving IVO 500 mg QD. Of samples with valid biomarker data, those with optimal 2-HG suppression (n = 21) showed upregulation of neural differentiation-related gene expression, but downregulation of stemness-related gene expression, vs those with suboptimal 2-HG suppression (post-treatment 2-HG above upper limit of wt IDH 2-HG levels; n = 17; p < 0.01). IHC analysis of the proliferation marker Ki-67 showed a ̃2-fold decrease in Ki-67–positive cells in samples with optimal 2-HG suppression (mean 2.7%; n = 22) vs those with suboptimal suppression (5.8%; n = 16; p < 0.05). Epigenetic analysis revealed a ̃2-fold increase in mean 5-hydroxymethylcytosine (5hmC) levels in samples with optimal (0.36%; n = 17) vs suboptimal 2-HG suppression (0.2%; n = 15; p < 0.05), suggesting reversal of TET2 inhibition. IHC analysis of TIME revealed increases in mean CD3+ and CD8+ tumor-infiltrating lymphocyte levels in samples with optimal (1.05% [CD3]/0.22% [CD8]; n = 22) vs suboptimal 2-HG suppression (0.44% [CD3]/0.07% [CD8]; n = 16; p < 0.05). Optimal 2-HG suppression was associated with upregulation of gene expression related to type I interferon signaling and antigen presentation (p < 0.01). Conclusions: These data suggest that both tumor-intrinsic and -extrinsic mechanisms underlie 2-HG suppression by VOR and IVO. VOR, and IVO to a lesser extent, increased 5hmC, promoted cellular differentiation, and inhibited tumor cell proliferation; both also increased T-cell infiltration, activated interferon signaling, and increased antigen presentation capability. These data support development of VOR in combination with immunotherapy. Clinical trial information: NCT03343197.

Molecular and morphological changes induced by ivosidenib correlate with efficacy in mutant-IDH1 cholangiocarcinoma

Background: IDH1 mutations occur in approximately 13% of intrahepatic cholangiocarcinomas (IHCCs). The oral, targeted, mutant IDH1 (mIDH1) inhibitor ivosidenib (AG-120) suppresses production of the oncometabolite D-2-hydroxyglutarate, promoting disease stabilization and improved progression-free survival (PFS) in mIDH1 IHCC. Materials & methods: Harnessing matched baseline and on-treatment biopsies, we investigate the potential mechanisms underlying ivosidenib's efficacy. Results: mIDH1 inhibition leads to decreased cytoplasm and expression of hepatocyte lineage markers in patients with prolonged PFS. These findings are accompanied by downregulation of biliary fate, cell cycle progression and AKT pathway activity. Conclusion: Ivosidenib stimulates a hepatocyte differentiation program in mIDH1 IHCC, a phenotype associated with clinical benefit. mIDH1 inhibition could be a paradigm for differentiation-based therapy in solid tumors. Clinical trial registration: NCT02073994 (ClinicalTrials.gov).

Abstract 2046: Inhibiting IDH mutations in low-grade glioma alters cellular function and the immune environment

Somatic mutations in the genes encoding the metabolic enzymes isocitrate dehydrogenase (IDH) 1 and 2 occur in many cancers, including glioma, cholangiocarcinoma, and acute myeloid leukemia. Mutant IDH (mIDH) proteins have a gain-of-function enzyme activity, catalyzing the reduction of alpha-ketoglutarate (α-KG) to the oncometabolite D-2-hydroxyglutarate (2-HG). 2-HG competitively inhibits α-KG-dependent enzymes, leading to epigenetic dysregulation and tumorigenesis. TET2 is an α-KG-dependent enzyme mediating the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), which leads to DNA demethylation. In mIDH tumors, TET2 activity is inhibited by 2-HG, leading to DNA hypermethylation. In addition, IDH mutations are associated with immune evasion in gliomas. IDH mutations are common in low-grade gliomas (LGG; WHO grade 2/3) and include mutations in IDH1 (~80%) and IDH2 (~4%). Ivosidenib (AG-120, IVO) is a first-in-class, oral inhibitor of mIDH1, and vorasidenib (AG-881, VOR) is an oral, potent, brain-penetrant inhibitor of both mIDH1 and mIDH2. In an ongoing perioperative study (NCT03343197), IVO and VOR demonstrated brain penetrance and &gt;90% suppression of 2-HG in resected mIDH1 gliomas after pre-operative treatment for approximately 4 weeks. In this analysis, we examined the cellular mechanisms underlying mIDH inhibition in LGG using resected tumor tissues collected following treatment with IVO and VOR. Optimal 2-HG suppression (defined by post-treatment 2-HG levels equal to or lower than the upper range of IDH wild-type tumor 2-HG levels) in IVO- or VOR-treated samples (n=17) led to a ~2-fold increase in 5hmC compared with untreated controls and banked reference samples (n=35; P=0.04). Furthermore, immunohistochemistry (IHC) analysis of the proliferation marker Ki-67 showed a ~3-fold decrease in the percentage of Ki-67-positive cells in IVO- or VOR-treated samples with optimal 2-HG suppression (n=21) compared with untreated controls (n=5; P=0.02). Tumor immune microenvironment analyses were also conducted. Comparing IVO- or VOR-treated samples (n=21) with untreated controls and banked reference samples (n=33), RNAseq analysis showed a ~2-fold decrease in the expression of tumor-associated macrophage markers CD68 (P=0.01) and CD163 (P=0.03) in mIDH oligodendrogliomas. In addition, IHC analysis from paired pre-treatment (archival) and post-treatment samples showed an increase of CD3+ T-cell infiltration (P=0.03) and CD8+ T-cell infiltration (P=0.01) in IVO- or VOR-treated samples with optimal 2-HG suppression (n=21). Single-cell RNAseq was conducted for a subset of samples, and the results will be presented. Overall, these data suggest that mIDH inhibition decreases DNA hypermethylation and tumor cell proliferation, and activates the immune microenvironment in mIDH LGG. In conclusion, these data elucidate the mechanisms underlying mIDH inhibition and support further development of mIDH inhibitors in mIDH LGG.

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Citation Format: Min Lu, Ingo K. Mellinghoff, Aaron Diaz, Jennie W. Taylor, Sung Choe, Ania Tassinari, Dongwei Zhu, Katie Sellers, Kha Le, Feng Tai, Islam Hassan, Shuchi S. Pandya, Lori Steelman, Bin Wu. Inhibiting IDH mutations in low-grade glioma alters cellular function and the immune environment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2046.

Abstract A05: Bronchial premalignant lesions have distinct molecular subtypes associated with future histologic progression

Squamous cell carcinoma (SCC) of the lung is a leading cause of cancer mortality in the U.S. due to late-stage diagnosis and lack of effective treatments. Lung SCC arises in the epithelial layer of the bronchial airways and is often preceded by the development of premalignant lesions (PMLs). The molecular alterations involved in the progression of PMLs to lung SCC are not clearly understood as not all PMLs progress to carcinoma. We hypothesize that molecular characterization of PMLs and nonlesion areas will allow us to identify alterations associated with histology and lesion progression.

We used mRNA sequencing to profile biopsies obtained from high-risk smokers undergoing lung cancer screening by auto-fluorescence bronchoscopy and CT at the Roswell Park Cancer Institute in Buffalo, NY. For each subject (n=49), a brushing of the airway field (normal fluorescing area) and endobronchial biopsies were collected over time in repeat locations with serial bronchoscopies. The discovery cohort, included 29 subjects, 197 biopsies, and 91 brushes, while the validation cohort included 20 subjects, 111 biopsies and 49 brushes. The mRNA-Seq data were aligned to hg19 using STAR, and gene/transcript levels were summarized using RSEM. Immune, stromal, and epithelial cell content were inferred using xCell. Biopsy molecular subtypes were discovered using consensus clustering in the discovery cohort and used to train a nearest centroid subtype predictor to assign subtypes in the validation cohort and the brushes.

We identified four distinct molecular subtypes in the discovery cohort bronchial biopsies using genes (n=3936) co-expressed across the the discovery cohort brushes and biopsies and two additional RNA-seq lung SCC-related datasets. One of the four molecular subtypes is enriched (p&lt;0.001) for samples with dysplasia histology, high basal cell content, and the classic SCC tumor subtype. These associations are replicated in the validation cohort. There is also significant concordance between the molecular subtypes defined in the biopsies and their corresponding brush from the normal-appearing airway. Genes associated with IFN-gamma signaling and T cell-mediated immunity were observed to be downregulated among lesions that remained stable or progressed to more severe histology within the high-grade subtype. Staining adjacent biopsies to those profiled revealed that decreased expression of genes related to T cell-mediated immunity is associated with decreased numbers of CD4+ and CD8+T cells within the lesions and the surrounding tissue.

We have identified four molecular subclasses of premalignant lung SCC lesions that may associate with prognosis. Molecular classification of PMLs may lead to biomarkers of future disease progression that could be used to stratify patients into prevention trials and to monitor efficacy of the treatment. Additionally, the results suggest that personalized lung cancer chemoprevention that targets specific cancer-related pathways or the immune system may have potential therapeutic benefits.

Citation Format: Jennifer E. Beane, Sarah Mazzilli, Ania Tassinari, Joshua Campbell, Christopher Moy, Michael Schaffer, Catalina Perdomo, David Jenkins, Mary Beth Pine, Gang Liu, Sherry Zhang, Hangqio Lin, Jessica Vick, Evan Johnson, Suso Platero, Christopher Stevenson, Marc Lenburg, Mary Reid, Samjot Dhillon, Avrum Spira. Bronchial premalignant lesions have distinct molecular subtypes associated with future histologic progression [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr A05.

Abstract 896: The airway field of injury reflects gene expression changes associated with the presence of lung squamous premalignant lesions

Lung squamous cell carcinoma (SCC) arises in the epithelial layer of the bronchial airways and is preceded by the development of premalignant lesions (PMLs). The molecular events involved in the progression of PMLs to lung SCC are not clearly understood as not all PMLs that develop go on to form carcinoma. In addition, the majority of lung cancer chemoprevention agents tested to date are ineffective. Molecular characterization of the airway field of injury in individuals with PMLs could provide novel insights into the earliest molecular events associated with carcinogenesis and identify biomarkers to guide lung cancer detection and chemoprevention.

RNA-sequencing was conducted on cytologically normal airway brushings from current and former smokers with (n = 50) and without (n = 25) PMLs as part of the British Columbia Lung Health Study. Linear modeling strategies were used to identify 280 differentialy expressed genes at FDR&lt;0.002 between subjects with and without PMLs. Pathway analysis using GSEA and ROAST revealed enrichment of genes involved in the electron transport chain and oxidative phosphorylation pathways in subjects with PMLs. These findings were validated by measuring the cellular bioenergetics of cultured epithelial cells from biopsies of PMLs and non-lesion areas. Baseline oxygen consumption rates were 2.5 fold higher (p&lt;0.001) and the spare respiratory capacity was 1.5 fold higher (p&lt;0.001) in PML cultures. These data suggest that metabolism-associated gene expression observed in the field of injury of PMLs is correlated with PMLs. In addition, there is a significant concordant enrichment (FDR&lt;0.05) between the signature and gene expression in PMLs adjacent to SCC tumors, in SCC tumors, and in the field of individuals with lung cancer. This concordance led to the development of a 200-gene biomarker that accurately predicts the presence of PMLs (AUC = 0.90 n = 17 independent samples). Importantly, this biomarker was also predictive (AUC -.72) of progression/stability vs. regression of these premalignant lesions in an independent cohort of cytologically normal airway brushings collected as part of the RPCI screening clinic (n = 18).

This is the first study to comprehensively profile gene expression changes in airway epithelial cells in the presence of PMLs. A subset of these changes reflects the earliest changes in the process of lung squamous cell carcinogenesis including the genes involved in cellular metabolism. However, the molecular alterations in the field of injury are dynamic as bronchial lesions either progress or regress these changes may be leveraged to monitor efficacy in chemoprevention trials. In addition monitoring molecular changes in high-risk smokers may identify smokers with PMLs that should receive lung cancer screening as well as lay the foundation for personalized lung cancer chemoprevention.

Citation Format: Sarah A. Mazzilli, Ania Tassinari, Yaron Gethalter, Gang Lui, Mary Pine, Stephen Lam, Mary Reid, Suso Platero, Marc Lenburg, Avrum Spira, Jennifer Beane. The airway field of injury reflects gene expression changes associated with the presence of lung squamous premalignant lesions. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 896.

Molecular diagnosis of Philadelphia chromosome-positive chronic myeloid leukemia

BACKGROUND

In virtually all Ph1 chromosome-positive CML patients, the breakpoint on chromosome 22 maps in a very restricted area of 5.8 Kb, which has been named "breakpoint cluster region" or "bcr". Several molecular probes of this region are presently available, and this makes the molecular diagnosis of CML a useful approach which can be particularly important in those cases in which cytogenetic analysis does not reveal the presence of a Ph1 chromosome. Here we report the problems and our experience during the molecular analysis of the 478 patients examined so far.

METHODS

Molecular analyses were performed after digestion of the DNA with 2 to 4 restriction enzymes and hybridization with different probes. Individual samples were subjected to PCR since no rearrangements had been obtained with Southern blotting.

RESULTS

Rearrangement bands were detected in all the samples examined. In 473 cases the breakpoint was located within the bcr. In one of these cases, it was detected only after PCR analysis, and in two cases only after the use of the PHL/BCR probe. In 5 cases the breakpoint was localized either 5' or 3' with respect to the bcr.

CONCLUSIONS

In this paper, the criteria for a correct molecular diagnosis of CML are presented. The "PHL/BCR" probe appeared to be very specific and time-saving, since it required only one digestion to evidence the rearrangement. Our results confirm the high specificity of the breakpoint on chromosome 22 in CML and the relatively rare incidence of molecular variants.

Cytogenetic events after bone marrow transplantation for Philadelphia chromosome positive chronic myeloid leukemia

Allogeneic bone marrow transplantation is the only way to cure patients with Ph1+ chronic myeloid leukemia. It is commonly assumed that, in order to obtain a cure for the patients, the leukemic clone must be completely destroyed by the conditioning treatment and the donor's bone marrow must repopulate the hemopoietic niches leading to a "complete chimera". However, cytogenetic analyses, supported by molecular ones, indicate that Ph1+ cells, far from being completely destroyed by chemo-radiotherapy may persist for a long time, probably in the majority of the patients. As demonstrated by the outcome of patients receiving T-cell depleted marrow, immune mechanisms must be involved in controlling and progressively reducing the size of the residual leukemic clone. Furthermore, immunodulating therapeutic strategies, represented by cyclosporin-A discontinuation or alpha interferon treatment, may successfully reduce the Ph1+ cell population even after a full relapse.

New type of Bcr/Abl junction in Philadelphia chromosome-positive chronic myelogenous leukemia

A new and rare type of Bcr/Abl junction between exon C3 of the 3' portion of the Bcr gene and Abl exon 2 has been identified in the leukemic cells of two Ph1-positive chronic myelogenous leukemia patients in chronic phase. This is the fourth type of Bcr/Abl junction so far identified in Ph1-positive hematologic malignancies and is a consequence of an unusual breakpoint position on chromosome 22 that falls approximately 20 kb downstream of the major breakpoint cluster region (bcr) of the Bcr gene. The new hybrid mRNA is 540 base pairs (bp) longer than that expressed by the K562 cell line and could codify for a Bcr/Abl protein carrying 180 additional aminoacids with respect to the larger P210 protein so far identified. The hematologic phenotype expressed by the two patients carrying this unusual type of Bcr/Abl rearrangement does not significantly differ from that commonly seen in chronic myelogenous leukemia.

ABL proteins in Philadelphia-positive acute leukaemias and chronic myelogenous leukaemia blast crises

The Philadelphia chromosome (Ph1) is present in 95% of chronic myelogenous leukaemias (CML) and 15% of acute lymphoblastic leukaemias (ALL). This cytogenetic marker is due to a t(9;22) translocation, which causes a rearrangement of the ABL oncogene. In order to better define the relationship between type of genomic rearrangement, variant ABL protein expressed and haematological phenotype, a series of Ph1-positive acute leukaemias, both myeloblastic (AML) and lymphoblastic, and several CML lymphoid blast crises have been analysed at the DNA and protein level. The results confirm the presence of the ABL protein P210 in all cases of CML, ALL and AML positive for rearrangement in the bcr region of chromosome 22, and, surprisingly, in one AML case apparently negative for bcr rearrangement. The ABL protein P190 was found to be present only in cases of ALL negative for bcr rearrangement. Polymerase chain reaction (PCR) analysis of the types of 9/22 junctions present in the mRNA of CML lymphoid blast crises showed no evidence of 'ALL-type' transcripts.

HTLV-I positive adult T-cell leukaemia-lymphoma: report of a typical case from Italy

A case of acute adult T-cell leukemia-lymphoma (ATLL) was observed in northeast Italy, presenting with fever, lymphadenomegaly, splenomegaly, hypercalcemia and renal failure. Leukaemic cells were morphologically typical, expressed a T-cell CD4+ phenotype, did not display any helper functions, and grew in vitro under supply of exogenous interleukin-2. Antibodies to human T-cell lymphotropic virus (HTLV-I) were found in the serum, and the virus was isolated from leukaemic cells. The family members who could be tested were seronegative. The patient had never travelled outside Italy, had never received blood transfusions and did not belong to any known categories at risk of viral disease transmission. Present knowledge of the epidemiology of HTLV-I infection warns that other cases of HTLV-I induced disease are expected to occur outside already recognised endemic areas. This case suggests that untraceable, presumably short-term exposures can also account for HTLV-I transmission.

Molecular and cytogenetic studies of a patient with Philadelphia-negative, BCR-positive chronic myeloid leukemia and t(12;12)(q13;p12)

A patient with Philadelphia (Ph1)-negative, breakpoint cluster region (bcr)-positive chronic myeloid leukemia (CML) is reported. Pulsed-field gel electrophoretic analysis demonstrated the comigration of both ABL and BCR sequences on the same BssHII and SacII fragment. Moreover, in situ hybridization studies demonstrated that ABL sequences had been moved from band 9q34 to 22q11 and that the additional t(12;12)(q13;p12) was not involved in the ABUBCR related translocation. Nevertheless, a possible role of oncogenes or regulatory sequences activated or inhibited by the additional translocation cannot be excluded.

Immunoglobulin DNA Analysis as a Marker of Clonality in the Follow-up of Patients with Hairy Cell Leukemia Treated with Alpha-Interferon

In fourteen patients with hairy cell leukemia (HCL) the configuration of the immunoglobulin (Ig) heavy chain genes was used as a marker of clonality, to monitor the response of the neoplastic population to treatment with alpha-interferon (a-IFN). In agreement with the morphological, hematological and immunological data, twelve of them showed, after a variable length of therapy, a complete disappearance of rearranged bands in peripheral blood cells. In one patient, who was treated less intensively, the molecularly-defined neoplastic population was still present on two consecutive determinations, whilst in the last patient persistence of disease was repeatedly documented despite prolonged A-IFN treatment. Three further cases were analyzed sequentially: in two, no rearranged bands could be found at repeated determinations; the third, who was in complete remission whilst on 3 × 10(6) U of α-IFN every other day, showed recurrence of disease nine months later when on a maintenance protocol with 3 × 10(6) U/weekly. Nine bone marrow specimens were also analyzed following treatment with α-IFN. In four a monoclonally rearranged band could still be detected, while in another four, reversal of fibrosis and hemopoietic recovery wits coupled with the absence of a molecularly recognizable neoplastic clone. In the last (case, persistence of disease paralleled the findings in the peripheral blood cells. These data indicate that α-IFPJ is capable of producing a specific cytolytic effect on the leukemic population in HCL, which in some cases may lead to complete clonal remissions. Analysis at the DNA level may represent a valuable tool towards monitoring the clinical course of HCL patients and for optimal individual therapeutic scheduling.

5q- and t(2;11) in a patient with M2 acute non-lymphocytic leukemia. Case report

A patient with M2-ANLL and a 46,XX,del(5)(q22q33), t(2;11)(p21;q24) karyotype is described. The diagnosis was made after a short period of myelodysplastic syndrome. After chemotherapy consisting of Daunorubicin and Arabinosylcytosine in continuous infusion, the patient reached a complete remission. The chromosome pattern described here has been observed in two other patients with refractory anemia and refractory anemia with excess of blasts, respectively. The breakpoints on the chromosomes 2, 5 and 11 allow us to hypothesize the involvement of N-myc, c-fms, GM-CSF and IL-3 genes.

Cytogenetic and molecular studies in patients with chronic myeloid leukemia and variant Philadelphia translocations

Out of 105 Philadelphia (Ph) positive chronic myeloid leukemia patients analyzed, six (5.7%) carried a variant Ph translocation, namely t(6;9;9;10;22)(q24;p13;q34;p15;q11); t(9;13;22)(q34;q21;q11);der(2)(2pter----2q31::9q21---- 9q34::22q11----22qter) and der(9)t(2;9) (9pter----9q21::2q31----2qter);t(7;9;22)(q11;q34 ;q11), 14q + ;t(7;9;22)(q35;q34;q11), and t(9;11;22) (q34;q13;q11), respectively. Five of these patients were analyzed with Southern blotting. Three of them showed an atypical molecular pattern; namely, the patient with t(9;13;22) showed no rearrangement in the breakpoint cluster region (bcr), the patient with t(7;9;22)(q35;q34;q11) showed a 3' deletion, and the patient with t(7;9;22), 14q + showed a bcr rearrangement 3' to the exon 4 of the M-BCR. Chromosome in situ hybridization studies demonstrated that in patient one, a two-step translocation occurred: the first step moved the 3' bcr from chromosome 22 to chromosome 9, and the second moved the terminal part of 22q, carrying the c-sis protooncogene, to 10p. Variant Ph translocations appear to be associated with atypical molecular breakpoints.

Ontogeny, gene rearrangements and immunophenotype of acute leukaemias

The progressive availability of more sophisticated technologies has over the last few years allowed a more precise definition of the biological properties of acute leukaemia cells. This, in turn, has enabled to recognize the ontogeny of practically all cases, with particular emphasis to acute lymphoblastic leukaemia, the lineage affiliation of which had, for many years remained uncertain in over half of the cases. Here, we shall review the main achievements, obtained with extensive immunotyping coupled to the use of probes for the immunoglobulin and T-cell receptor genes, which have led to these important clinico-biological acquisitions, and discuss specific situations in which this combined phenotypic and genotypic approach (as well as response to cloned growth factors) may be of particular value.

Evaluation of complete remission in hairy cell leukemia patients treated with alpha-IFN

In 10 HCL patients, who following treatment for more than 1 year with alpha-IFN, had achieved a normalization of the splenomegaly and a disappearance of circulating hairy cells together with a complete restoration of all peripheral hematological values, a multiple assessment of the apparent complete remission (CR) was carried out. The presence of residual disease was investigated by bone marrow histology, bone marrow immunohistochemistry, immunoglobulin (Ig) gene analysis and on the basis of the serum levels of the soluble form of the Interleukin-2 receptor (sIL-2R). Examination of bone marrow biopsies showed a pattern of CR in 5 cases; 4 of them revealed no evidence of Ig heavy chain gene rearrangement, as well as a near normalization of the serum levels of sIL-2R. Immunohistochemical studies were carried out on embedded paraffin sections with the monoclonal antibody 4KB5 (CD45R) and were assessable in 4 of the 5 patients considered in CR and in 3 of the 4 cases with no Ig gene rearrangement. In 2 the pattern of CR was confirmed, while in the 3rd a minimal but persistent disease (5%) was suspected.

Molecular characterization of Ph' + hybrid acute leukemia

The configuration of the immunoglobulin heavy chain (IgH), T-cell receptor (TcR) beta and gamma chain regions, and the major breakpoint cluster region (M-bcr) genes were analysed in four cases of Ph' + acute leukemia (AL). Monoclonal rearrangements of the IgH region were detected in three cases exhibiting two phenotypically distinct cell populations (i.e. one lymphoid and one myeloid. In one of these cases, identical genetic events were observed by molecular analysis of FACS separated blasts. Multi-lineage rearrangements involving also the TcR gamma gene were observed in a biphenotypic AL showing co-expression of markers. The lack of rearrangements within the M-bcr gene, together with demonstration in one case of the Ph' + AL specific p190 protein product, pointed against the occurrence of chronic myeloid leukemias presenting in blastic transformation. Our results imply that such cases are to be considered as true AL and should therefore be included in the definition of hybrid AL.

Variability of the molecular defects corresponding to the presence of a Philadelphia chromosome in human hematologic malignancies

By analyzing a total of 107 patients affected by chronic myelogenous leukemia (CML; chronic and blast crisis) or lymphoid and myeloid Philadelphia chromosome (Ph') positive acute leukemias, we have investigated the relationship between the molecular defect on the Ph' chromosome and the associated hematologic phenotype. As expected, approximately half of the Ph' positive acute leukemias showed a breakpoint on chromosome 22 falling outside the "breakpoint cluster region" (bcr) known to be involved in CML. Surprisingly, seven of 80 CML cases in chronic phase also showed rearrangements falling outside the bcr region. In two of these cases the breakpoint on chromosome 22 was mapped between 9 and 12 kb upstream to the bcr region. In another case, the breakpoint was located approximately 16 kb downstream to bcr. In the remaining four cases, the precise position of the rearrangement could not be localized with the available bcr probes. DNAs from patients with CML blast crises showed classical bcr rearrangements. No molecular changes were observed during the progression of the disease in six patients whose DNA from both a chronic and acute phase was available. Our results seem to indicate a greater degree of variability of chromosome 22 breakpoints in CML than previously observed, and the lack of additional rearrangements on the Ph' chromosome in CML blast crises with respect to chronic phase.

Cytoskeleton organization of normal and neoplastic lymphocytes and lymphoid cell lines of T and B origin

An anomalous organization of the cytoskeleton has been described in lymphocytes from chronic lymphatic leukaemia and in only few cell lines. We have now studied normal and neoplastic lymphocytes and lymphoid cell lines of both T and B lineage in order to detect morphological differences in the expression of microfilaments and intermediate filaments. Microfilaments appear to be well expressed by all the B cells, whereas a rich network of intermediate filaments is present in T cells and plasma cells. Most prominent changes occur in the latter system, which is almost lacking in cells of B chronic lymphatic and hairy cell leukaemia. Although the significance of the present findings is not yet clear, one might speculate that such alterations account for some of the aberrant functions and peculiar biologic properties of neoplastic lymphocytes.

Multilineage cell involvement in Ph1-negative, bcr-negative chronic myeloid leukemia

We report a case of Ph1-negative, bcr-negative CML-BC, in which the primary leukemic cells displayed T-related antigens (CD7, CD4) in addition to HLA-DR and CD25 determinants. No B-lymphoid, myeloid and megakaryoblastic surface antigens were detected. In spite of this phenotype, DNA analysis revealed a germ-line configuration of the T-cell receptor beta chain gene region. Moreover, in-vitro culture studies demonstrated a proliferative response of the blast cell population to natural and recombinant myeloid-related factors, while no proliferative signal was observed in the presence of IL-2. The myeloid lineage was further demonstrated by the expression of myeloid-associated antigens on cultured blast cells, which still retained the CD7 antigen. Finally, cytogenetic analysis revealed a monosomy 7 which is usually associated with a stem cell leukemia. These results support the hypothesis that Ph1-negative, bcr-negative CML is characterized by the involvement of a multipotent stem cell capable of multilineage expression and indicate that differentiative and proliferative assays provide a further tool towards a more precise recognition of hematological disorders of uncertain origin.

Germ-line configuration of the T-cell receptor beta-chain gene in B-cell chronic lymphoproliferative disorders which co-express T-cell antigens

In 7 cases of chronic B-cell lymphoproliferative disorders-6 chronic lymphocytic leukaemias and 1 non-Hodgkin lymphoma in leukaemic phase--which co-expressed T-cell markers (CD3, CD2) the clonal origin was investigated at the DNA level. In accordance with the diagnosis, all cases showed a monoclonally rearranged configuration of the immunoglobulin genes. On the contrary, the T-cell receptor beta chain gene always retained a germ-line organization. These findings demonstrate that B-cell chronic lymphoproliferative disorders which co-express T-cell-related markers are truly composed of monoclonal B-cell elements.

Close association between antibodies to cytoskeletal intermediate filaments, and chronic graft-versus-host disease

Chronic graft-versus-host disease can mimic various autoimmune disorders, although autoantibodies are rarely detected in the sera of affected patients. Antibodies to cytoskeleton are a frequent finding in patients affected by autoimmune disorders. In all the sera of 16 patients who were submitted to allogeneic bone marrow transplantation, we have found antibodies against cytoskeletal intermediate filaments. Moreover, the titer of such antibodies is quite elevated when compared with those reported in autoimmune disorders. A statistically significant difference between the titers found in patients without and with cGVHD (median 1:40 vs. 1:256, P less than 0.05) has been found. This would suggest that such antibodies might be relevant in monitoring clinical course. Furthermore, since certain cytoskeleton antigens have been shown to be expressed also on cell membrane, antibodies against intermediate filaments might also play a more important role by interfering with such surface structures.

Chronic T-cell leukaemias. A variant of T-prolymphocytic leukaemias: morphological, immunological and clinical characterization of 2 cases

In this study we describe 2 patients who appear to suffer from a morphological, cytochemical and clinico-haematological variant of T-prolymphocytic leukaemia (T-PLL). The cells were smaller than typical prolymphocytes, with a regular nucleus containing a smaller and less prominent nucleolus; the alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (AP) cytochemical reactions showed a weaker pattern of positivity in this variant compared to T-PLL. No immunological differences were found between the two conditions with regard to membrane expression and functional behavior of the cells. The clinical course and the outcome of the patients appears to be different: aggressive and rapidly fatal in T-PLL; thus far well-controlled in the T-PLL variant. From a molecular point of view, both cases showed a monoclonal rearrangement of the T-cell receptor beta-chain gene.

Configuration of the immunoglobulin and T cell receptor gene regions in hairy cell leukemia and B-chronic lymphocytic leukemia

The configuration of the immunoglobulin heavy and light chain genes and of the T cell receptor (TCR) beta region was examined in a series of patients with hairy cell leukemia (HCL) and compared with the findings in B cell chronic lymphocytic leukemia (B-CLL). In all cases of HCL and B-CLL studied a rearrangement of the immunoglobulin heavy chain loci coupled to a reorganization of the light chain genes was documented. However, in all HCL and all but one B-CLL the TCR beta gene region was in a germ-line configuration. These findings confirm that HCL is characterized by the expansion of relatively mature B cell elements with a molecular configuration similar to that of B-CLL and indicate that the reported expression of T cell related markers, particularly in B-CLL, is not coupled to a rearrangement of the TCR beta-chain gene. Analyses of the immunoglobulin gene regions in HCL represent an important diagnostic tool as well as a possible aid toward monitoring the response to treatment.

Role of target and effector cell structures in natural killer-mediated cytotoxicity

An analysis of target and effector cell structures involved in the in vitro natural killer (NK)-mediated cytotoxicity has been performed. The degree of surface expression of transferrin receptor (TR) was only in part correlated with that of cell lysis. Moreover, the lysis could not be blocked by treating target cells with two anti-TR monoclonal antibodies. Finally, cell lines poorly affected by NK cells express TR only at the cytoplasmic level. As to the effector cells, the integrity of cytoskeleton components (especially microtubules) was found to be essential for the occurrence of cell lysis. In fact, vinblastine, an anti-microtubule agent, was able to significantly reduce the percentage cell lysis. This effect was not due to a selective depletion in NK cells induced by the drug. It is concluded that the mechanisms underlying NK activity are complex and involve both target and effector cell structures.

[Radiologic aspects of lung morphology: lobulus and acinus (author's transl)]

Primary lobule, acinus and secondary lobule are the three basic elements of lung tissue. In order to visualize these structures slices of fixed lungs are documented radiologically by plain films, angio-, and bronchograms. Characteristic pathologic alterations of these elements are edema and inflammation. Both lesions present with atypical radiological pattern. In pneumonia it is shown, that differentiation of air conducting structures of the bronchial tree and structures which are involved in gas exchange appears most valuable for interpretation of confluent densities. According to our experience based upon examination of 143 lung specimens separation into lobules is pathophysiological more important than the organisation into the next smaller unit--the acini: patterns of acinar radiodensities are extremely rare and might sometimes be imitated by peribronchial infiltrations.