[Show abstract][Hide abstract] ABSTRACT: Although tyrosine kinase inhibitors have improved survival in advanced gastrointestinal stromal tumor (GIST), complete response is rare and most patients eventually fail the first-line treatment with imatinib. Sunitinib malate is the only approved second-line therapy for patients with imatinib-resistant or imatinib-intolerant GIST. The clinical benefit of sunitinib is genotype-dependent in regards to both primary and secondary mutations, with GIST patients harboring the KIT(AY502-3ins) exon 9 mutation being the most sensitive.
As sunitinib resistance is now emerging, our goal was to investigate mechanisms of progression and to test the efficacy of novel tyrosine kinase inhibitor on these resistant mutants in vitro. N-ethyl-N-nitrosourea mutagenesis of Ba/F3 cells expressing the KIT(AY502-3ins) mutant was used to investigate novel patterns of resistant mutations evolving in the presence of sunitinib.
Tumors from patients who developed sunitinib resistance after at least 1 year of radiographic response were analyzed, showing similar findings of a primary KIT(AY502-3ins) mutation and a secondary mutation in the KIT activation loop. Ba/F3 cells expressing these sunitinib-resistant double mutants showed sensitivity to both dasatinib and nilotinib.
Sunitinib resistance in GIST shares similar pathogenetic mechanisms identified in imatinib failure, with acquisition of secondary mutations in the activation domain after an extended initial response to the drug. Moreover, in vitro mutagenesis with or without N-ethyl-N-nitrosourea of Ba/F3 cells expressing KIT(AY502-3ins) showed acquisition of secondary mutations restricted to the second kinase domain of KIT. In contrast, in vitro resistance to imatinib produces a broader spectrum of secondary mutations including mutations in both KIT kinase domains.
Full-text · Article · Oct 2009 · Clinical Cancer Research
[Show abstract][Hide abstract] ABSTRACT: To assess the usefulness of 4-hydroperoxycyclophosphamide (4-HC) and Etoposide (VP-16) as a purging agent for myeloma cells in bone marrow ex-vivo, myeloma cell lines (SK-RCS-1, RPMI-8226), lymphoma cell line (SK-DHL-2) and normal bone marrow (BM) cells were treated at different concentrations of 4-HC, VP-16. In separate experiments, LAK cells or antibodies were also used to treat the above cell lines. Clonogenic tumor cells from all three cell lines could be reduced by more than 4 logs, when treated alone or as a mixture with irradiated normal bone marrow cells at a 4-HC concentration of 60 μmol/l. Under similar conditions, approximately 1% of normal BM myeloid progenitor granulocyte-macrophage colony forming cells (CFU-GM) survived. The results with LAK cells and antibodies were also encouraging. These observations support the use of various purging methods for myeloma cells for autologous bone marrow transplantation.
No preview · Article · Apr 2009 · European Journal Of Haematology
[Show abstract][Hide abstract] ABSTRACT: Resistance is commonly acquired in patients with metastatic gastrointestinal stromal tumor who are treated with imatinib mesylate, often due to the development of secondary mutations in the KIT kinase domain. We sought to investigate the efficacy of second-line tyrosine kinase inhibitors, such as sorafenib, dasatinib, and nilotinib, against the commonly observed imatinib-resistant KIT mutations (KIT(V654A), KIT(T670I), KIT(D820Y), and KIT(N822K)) expressed in the Ba/F3 cellular system.
In vitro drug screening of stable Ba/F3 KIT mutants recapitulating the genotype of imatinib-resistant patients harboring primary and secondary KIT mutations was investigated. Comparison was made to imatinib-sensitive Ba/F3 KIT mutant cells as well as Ba/F3 cells expressing only secondary KIT mutations. The efficacy of drug treatment was evaluated by proliferation and apoptosis assays, in addition to biochemical inhibition of KIT activation.
Sorafenib was potent against all imatinib-resistant Ba/F3 KIT double mutants tested, including the gatekeeper secondary mutation KIT(WK557-8del/T670I), which was resistant to other kinase inhibitors. Although all three drugs tested decreased cell proliferation and inhibited KIT activation against exon 13 (KIT(V560del/V654A)) and exon 17 (KIT(V559D/D820Y)) double mutants, nilotinib did so at lower concentrations.
Our results emphasize the need for tailored salvage therapy in imatinib-refractory gastrointestinal stromal tumors according to individual molecular mechanisms of resistance. The Ba/F3 KIT(WK557-8del/T670I) cells were sensitive only to sorafenib inhibition, whereas nilotinib was more potent on imatinib-resistant KIT(V560del/V654A) and KIT(V559D/D820Y) mutant cells than dasatinib and sorafenib.
Preview · Article · Sep 2007 · Clinical Cancer Research
[Show abstract][Hide abstract] ABSTRACT: Activating mutations in either BRAF or NRAS are seen in a significant number of malignant melanomas, but their incidence appears to be dependent to ultraviolet light exposure. Thus, BRAF mutations have the highest incidence in non-chronic sun damaged (CSD), and are uncommon in acral, mucosal and CSD melanomas. More recently, activating KIT mutations have been described in rare cases of metastatic melanoma, without further reference to their clinical phenotypes. This finding is intriguing since KIT expression is downregulated in most melanomas progressing to more aggressive lesions. In this study, we investigated a group of anal melanomas for the presence of BRAF, NRAS, KIT and PDGFRA mutations. A heterozygous KIT exon 11 L576P substitution was identified in 3 of 20 cases tested. The 3 KIT mutation-carrying tumors were strongly immunopositive for KIT protein. No KIT mutations were identified in tumors with less than 4+ KIT immunostaining. NRAS mutation was identified in one tumor. No BRAF or PDGFRA mutations were identified in either KIT positive or negative anal melanomas. In vitro drug testing of stable transformant Ba/F3 KIT(L576P) mutant cells showed sensitivity for dasatinib (previously known as BMS-354825), a dual SRC/ABL kinase inhibitor, and imatinib. However, compared to an imatinib-sensitive KIT mutant, dasatinib was potent at lower doses than imatinib in the KIT(L576P) mutant. These results suggest that a subset of anal melanomas show activating KIT mutations, which are susceptible for therapy with specific kinase inhibitors.
Full-text · Article · Jul 2007 · International Journal of Cancer
[Show abstract][Hide abstract] ABSTRACT: Cytofluorographic analysis of surface immunoglobulin (sIg) light chain clonal excess (CE), defined as (%kappa+ - %lambda+)/(%kappa+ + %lambda+) cells per discrete level of fluorescence intensity, was carried out on mononuclear cells of 32 leukemic patients. Eight demonstrated sIg light chain CE, including four blastic chronic myeloid leukemias (BL-CML), three "null" acute lymphoblastic leukemias (ALL), and one leukemic lymphoblastic lymphoma. Six of the leukemias demonstrated a kappa CE and two had a lambda CE. Sorted kappa+ PB cells from a BL-CML patient were shown to have a diploid DNA stem line and to bear the "common" ALL antigen. To provide further support for our finding of the expression of sIg light chains in ALL, we studied the REH cell line, derived from a "common" ALL patient and found cytoplasmic mu heavy chain and surface Ig lambda CE. Nucleic acid blotting experiments on REH revealed that both kappa genes had been deleted and that lambda genes had been rearranged, as expected in B cells expressing lambda light chains. Moreover, REH cells contained mu and lambda RNA. When REH cells were treated with TPA the amount of mu chain RNA increased by approximately fivefold and the amount of lambda chain RNA increased by approximately twofold. The finding of sIg light chain in pre-B cell leukemias and in the REH cell line, suggests that these leukemic cells are further differentiated along the B-cell lineage than was previously believed.
No preview · Article · Dec 2006 · Annals of the New York Academy of Sciences
[Show abstract][Hide abstract] ABSTRACT: The 9;22 chromosomal translocation characteristic of CML results in a fused bcr/abl gene and an abnormal fusion protein, p210bcr/abl. Relative to normal c-abl, p210bc1/abl has elevated tyrosine kinase activity that is essential for its transforming activity. We recently reported a prominent 62 kDa GAP-associated P-tyr protein and five additional consistent but less prominent P-tyr proteins as well as five more minor P-tyr proteins that are constitutively tyrosine phosphorylated in primary primitive lineage negative (lin-) chronic phase CML blasts but not in comparable primary lin- normal blasts. The GAP-associated p62 protein has now been purified, sequenced and its gene has been cloned; it is a previously unidentified protein and is currently being characterized. In analyzing P-tyr proteins in primary lin- normal blasts in response to various hematopoietic cytokines, we found a striking similarity in the tyrosine phosphorylation of four major and three minor proteins after stimulation with c-kit ligand (KL) and the P-tyr proteins that are constitutively phosphorylated in primary primitive lin- chronic phase CML blasts. Other cytokines tested (ie GM-CSF, G-CSF, IL-3, FLT3 ligand, TPO, EPO) were much less active or stimulated phosphorylation of other proteins. KL/c-kit and bcr/abl have some similar activities including enhancing survival and expansion of hematopoietic progenitor cells, probably acting primarily on early progenitors at the time of lineage commitment rather than on self-renewing stem cells. Activation of growth factor receptors promote a cascade of protein phosphorylations that can ultimately result in a wide range of cellular responses. Sustained activation of discrete signaling pathways in some types of cells results in differentiation, whereas transient activation instead causes a proliferative response; in other cell types, the converse is true. It may be postulated that stem cells and primitive progenitors are at a particularly susceptible stage of development that renders them especially responsive to sustained bcr/abl-induced phorphorylation of a number of signaling proteins that are components of critical regulatory pathways, including c-kit. The affected pathways control and coordinate multiple diverse cell processes including proliferation, differentiation, maturation and apoptosis, processes that are normally tightly regulated and integrated. Perturbation of these key pathways in primitive progenitors would be expected to seriously disrupt orderly hematopoiesis and could also explain the multiple subtle pleiotropic biological abnormalities characteristically observed in later maturing CML compartments that we have collectively designated 'discordant maturation'. The true situation is undoubtedly very complex and involves interaction of multiple cytokines and signaling pathways that we are now trying to define. Constitutive downstream activation of critical pathways in susceptible early progenitors that normally require KL or other factors for activation could explain most if not all features of the disease.
[Show abstract][Hide abstract] ABSTRACT: The purpose of the present work were to identify the initial characteristics associated with long-term survival in chronic granulocytic leukaemia (CGL) and to analyse the accuracy of prognostic models in identifying long-term survivors. 813 Philadelphia (Ph) chromosome-positive, nonblastic CGL patients from six American and European institutions, the majority treated conventionally, with a minimum follow-up > 10 years, were studied. Stepwise logistic regression was performed to ascertain the association between the initial clinicohaematological variables and survival > or = 8 years, and a prognostic index was derived. The usefulness of both Sokal's and the new prognostic index to identify long-term survivors was assessed by calculating their positive and negative predictive accuracies, sensitivity and specificity. Median survival of the series was 45 months (range 1-255), with 784 patients (96.4%) having died and 109 (13.4%) surviving 8 years or longer. Younger age, smaller spleen, platelets < or = 600 x 10(9)/l, and lower blood blast percentage were associated with survival > or = 8 years; platelets < or = 600 x 10(9)/l and lower blood blast percentage were the predictive factors in patients 50 years old or younger. Two-thirds of long survivors belonged to Sokal's low-risk group, but the positive predictive accuracy and specificity for prolonged survival of Sokal's index were very low. This was also the case for the new predictive index.(ABSTRACT TRUNCATED AT 250 WORDS)
No preview · Article · Jul 1994 · British Journal of Haematology
[Show abstract][Hide abstract] ABSTRACT: Laboratory studies have suggested that hematopoietic growth factors (GF), combined with cytosine-arabinoside (Ara-C) can enhance cytotoxic effects of this agent against acute myeloid leukemia (AML) cells. While clinical trials based on this growth factor/chemotherapy combination (GF/CT) are progressing with discordant results, further information regarding the underlying mechanisms have been reported supporting this rationale and requiring additional investigation. To assess the role of cytokinetic changes in the GF/CT strategy and to evaluate if chemotherapeutic agents regimens other than Ara-C, when combined with GF, can enhance their cytotoxic effects, we have primed AML blasts with two cytokine combinations and then exposed these cells to the S-phase specific agent Ara-C as well as to the phase non-specific drug daunorubicin (DNR) and to the alkylating agent 4-hydroperoxycyclophosphamide (4-HC). The two cytokine combinations used for priming AML blasts were: (i) interleukin-3 (IL-3) + granulocyte-macrophage colony-stimulating factor (GM-CSF) + granulocyte colony-stimulating factor (G-CSF); and (ii) GM + G-CSF. Cytokinetic analysis in ten AML samples and clonogenic growth of leukemic colonies (CFU-L) in methylcellulose were used to detect proliferative and cytotoxic effects on AML samples. We report that in AML clonogenic cell growth can be stimulated by cytokines in 50% of the samples (4/8), and that Ara-C sensitization clearly occurs in two out of these four samples. Among the different cytokine combinations tested, the one containing IL-3 was the most effective through a cytokinetic mechanism consistent with recruitment (averaged G0 decrease p = 0.04; S-phase increase p = 0.005). Furthermore we observed increased cytotoxicity also to the phase non-specific drugs DNR and 4-HC, which may be mediated by other mechanisms recently described. We conclude that GF/CT combinations may also be beneficial in regimens containing drugs other than Ara-C, used for AML treatment, including bone marrow transplantation conditioning regimens.
[Show abstract][Hide abstract] ABSTRACT: The purposes of the present work were to identify the initial characteristics associated with long-term survival in chronic granulocytic leukaemia (CGL) and to analyse the accuracy of prognostic models in identifying long-term survivors. 813 Philadelphia (Ph) chromosome-positive, nonblastic CGL patients from six American and European institutions, the majority treated conventionally, with a minimum follow-up < 10 years, were studied. Stepwise logistic regression was performed to ascertain the association between the initial clinicohaematological variables and survival ≤8 years, and a prognostic index was derived. The usefulness of both Sokal's and the new prognostic index to identify long-term survivors was assessed by calculating their positive and negative predictive accuracies, sensitivity and specificity. Median survival of the series was 45 months (range 1-255), with 784 patients (96.4%) having died and 109 (13.4%) surviving 8 years or longer. Younger age, smaller spleen, platelets ≤600 × 109/I, and lower blood blast percentage were associated with survival ≤8 years; platelets ≤ 600 × 109/I and lower blood blast percentage were the predictive factors in patients 50 years old or younger. Two-thirds of long survivors belonged to Sokal's low-risk group, but the positive predictive accuracy and specificity for prolonged survival of Sokal's index were very low. This was also the case for the new predictive index. In 366 patients with information on the presence or not of additional karyotypic abnormalities at diagnosis, younger age, platelets ≤ 600 × 109/I, lower blood blast percentage, and absence of additional cytogenetic abnormalities were associated with survival ≤8 years. The addition of the cytogenetic data improved the positive predictive accuracy and specificity of the model, albeit modestly. We conclude that, although most CGL long survivors show favourable prognostic features at presentation, clinicohaematological data do not allow a precise definition of such a subpopulation.
No preview · Article · Jun 1994 · British Journal of Haematology
[Show abstract][Hide abstract] ABSTRACT: Nonparametric maximum likelihood estimation of the probability of failing from a particular cause by time t in the presence of other acting causes (i.e., the cause-specific failure probability) is discussed. A commonly used incorrect approach is to take 1 minus the Kaplan-Meier (KM) estimator (1 – KM), whereby patients who fail of extraneous causes are treated as censored observations. Examples showing the extent of bias in using the 1-KM approach are presented using clinical oncology data. This bias can be quite large if the data are uncensored or if a large percentage of patients fail from extraneous causes prior to the occurrence of failures from the cause of interest. Each cause-specific failure probability is mathematically defined as a function of all of the cause-specific hazards. Therefore, nonparametric estimates of the cause-specific failure probabilities may not be able to identify categorized covariate effects on the cause-specific hazards. These effects would be correctly identified by cause-specific cumulative hazard or KM plots in which the extraneous causes of failure are treated as censored observations. Examples are provided. Finally, nonparametric graphical representation of the two distinct cause-specific failure components of the mixture model (i.e., the probability of ever failing from a particular cause and the time-to-failure distribution given that a patient will fail of that cause) are presented. The difficulty in extrapolating the nonparametric estimates beyond the range of observed failure times is highlighted. In addition, the mathematical relationship of a single covariate z and the two cause-specific failure components is shown for the case where z acts multiplicatively on the cause-specific hazards. Examples are considered using the important prognostic factors in adult soft tissue sarcoma (STS) of the extremity and adult acute lymphoblastic leukemia (ALL). In each of the mathematical and actual examples considered, the characteristic that was associated with a higher hazard rate of failure from the disease was also associated with a higher probability of ever failing from the disease as well as a shorter time-to-failure distribution given that failure due to the disease will occur. Thus it may be quite common in chronic disease situations to find prognosticators that are associated with both cause-specific failure components.
No preview · Article · Jun 1993 · Journal of the American Statistical Association
[Show abstract][Hide abstract] ABSTRACT: In a prospective randomized manner, this study evaluated the effect of adjuvant chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisone; CHOP) in patients with Stage I non-Hodgkin lymphoma (NHL) who have achieved a complete response (CR) after radiation therapy (RT).
Forty-four patients with clinical or pathologic Stage I intermediate-grade or low-grade NHL were randomized to receive regional RT alone (median dose, 40 Gy) or regional RT followed by six cycles of CHOP chemotherapy. There were no differences in clinical and pathologic characteristics between the two treatment groups.
The median follow-up was 7 years (range, 2-10 years). The actuarial relapse-free survival (RFS) rate for the RT plus CHOP group at 7 years was 83% compared with 47% (P < 0.03) for the RT-alone group. The overall survival (OS) for the two groups was 88% and 66%, respectively (P = 0.2). In patients with intermediate-grade NHL, the 7-year actuarial RFS for RT and CHOP was 86% compared with 20% for RT alone (P = 0.004). The corresponding actuarial survival rates were 92% and 47%, respectively (P = 0.08). In patients with low-grade histologic findings, the addition of adjuvant CHOP did not improve RFS (P = 0.6) or OS. All relapses in this study were at sites remote from the initially involved areas, and in 5 of 11 patients (45%), there were recurrences 5 years or longer after initial treatment.
This study showed that adjuvant CHOP chemotherapy significantly improves RFS in patients with Stage I intermediate-grade NHL who achieve a CR after regional-field RT. The chemotherapeutic regimen favorably affected their probability of survival.
[Show abstract][Hide abstract] ABSTRACT: In this study we have investigated the ability of transforming growth factor-beta 3 (TGF-beta 3, 1000 pM) to protect hematopoietic bone marrow (BM) progenitor cells from the cytotoxic activity of 4-hydroperoxycyclophosphamide (4-HC, 100 microM) in vitro. Hematopoietic progenitors were purified by negative depletion of accessory and maturing cells or enriched by positive (CD 34+ cells) selection. For comparison the same treatment was tested on three different lymphoid cell lines CEM, SK-DHL-2, and LY-16. The experimental protocol was designed to mimic ex vivo purging conditions. Therefore, tumor cells and enriched hematopoietic precursors were mixed with irradiated BM cells. Our results demonstrated that preincubation of enriched progenitor cells with TGF-beta 3 for up to 72 h followed by 4-HC treatment resulted in an increased survival of colonies derived from granulocyte-macrophage (CFU-GM) and erythroid (BFU-E) colony-forming cells, whereas a substantially lower number of colonies was observed in the control group. Similar results were observed when BM cells were first treated with 4-HC followed by TGF-beta 3 incubation for 24 or 48 h. In contrast, TGF-beta 3 provided no protection to the 4-HC cytotoxicity toward the lymphoma and leukemia cell lines. Three to four log of tumor cell killing was induced by 4-HC in the presence or absence of preincubation with TGF-beta 3. These data suggest that TGF-beta 3 is able to protect normal BM progenitors from the cytotoxic activity of an alkylating agent (4-HC) in vitro, whereas it does not offer any protection to lymphoma cell lines. These findings will have important implications for developing better purging conditions for autologous GM transplantation.
No preview · Article · Jan 1993 · Experimental Hematology
[Show abstract][Hide abstract] ABSTRACT: We compared the recovery of human hematopoietic progenitors in long-term bone marrow culture (LTBMC) initiated in tissue culture (TC) flasks to that in "Lifecell" bags, which are gas-permeable plastic bags in which feeder-layer cells cannot adhere. Our results showed that granulocyte-macrophage colony-forming unit (CFU-GM) and erythroid burst-forming unit (BFU-E) cumulative recovery in cultures from normal donor marrow, expressed as a percent of the initial inoculum, was not statistically different in the two culture systems up to week 8, when the cultures were terminated: 31.5 +/- 19 (flask) vs 30 +/- 14 (bag) and 15.5 +/- 12 (flask) vs 11.5 +/- 8 (bag), respectively. The effects of weekly addition of recombinant human (r-hu)-interleukin 1 (IL1) and r-hu-interleukin 3 (IL3) were then studied, alone and combined, at two different concentrations. Addition of IL1, either alone or combined with IL3, in LTBMC established in flasks induced an increase of hematopoietic progenitors for the first week, but BFU-E and CFU-GM were no longer detectable at weeks 4 and 6, respectively. Analysis of adherent layer cells showed a decreased cellularity, no adipogenesis, and early disappearance of bone marrow (BM) progenitors, whereas the cycling rate of myeloid precursors, by cytosine arabinoside (Ara-C) suicide assay, was similar to that of untreated cultures. Conversely, IL3 alone (5 ng/ml) resulted in 3.6- and 5.4-fold peak increases for CFU-GM and BFU-E, respectively, at week 1 (adherent plus nonadherent cells), and the recovery of BM cells was still higher than that of control flasks at week 8. By comparison, stimulation with colony-stimulating factors (CSFs) of BM cells grown in bags never affected the longevity of the culture. Addition of IL3 (5 ng/ml) induced a higher recovery of total cells, CFU-GM (range: 1.6- to 15-fold peak increase during the culture), and BFU-E (1.2- to 3-fold) compared to the untreated controls. Bags treated with IL1 alone demonstrated only transient beneficial effects, and the number of hematopoietic precursors fell below the level of control bags during the culture. IL1 and IL3 induced 1.8- and 5.3-fold peak increases in BFU-E and CFU-GM at weeks 1 and 4, respectively. Simultaneous flow cytometric analysis of CD34+/CD33+ cells and DNA content showed increased numbers and proliferation of the committed BM progenitors when CSFs were added to the bag.(ABSTRACT TRUNCATED AT 400 WORDS)
No preview · Article · Jul 1992 · Experimental Hematology
[Show abstract][Hide abstract] ABSTRACT: Suppression or eradication of the Philadelphia (Ph1) chromosome has been a major goal in the therapy of chronic myelogenous leukemia (CML). Variable levels of Ph1 chromosome negativity have been achieved using interferon-alfa, busulfan, combination chemotherapy, and allogeneic bone marrow transplantation. This study evaluated the effect of achieving a predetermined level of myelosuppression using hydroxyurea on bone marrow cytogenetics in CML. Fourteen patients with chronic phase CML received 25 cycles of therapy. Fourteen of the 25 cycles were associated with cytogenetic responses consisting of 25% or more Ph1 negative metaphases (range, 25% to 100%). Nine of the responses consisted of 50% or greater Ph1 negative metaphases. Toxicity was exclusively due to consequences of myelosuppression, including febrile neutropenia and thrombocytopenia. In chronic phase CML, hydroxyurea induces cytogenetic responses with tolerable toxicity and is an attractive agent for further study as a component of treatment strategies aimed at eradicating the Ph1 + population in CML.
No preview · Article · Jul 1992 · Seminars in Oncology
[Show abstract][Hide abstract] ABSTRACT: To achieve a high percentage of durable complete remissions (CR) and prolonged survivals and reduce toxicity in patients with early-stage and intermediate-stage Hodgkin's disease, a randomized trial of four cycles of mech-Iorethamine, vincristine, procarbazine, and prednisone (MOPP) versus four cycles of thiotepa, bleomycin, and vinblastine (TBV) combined with regional radiation therapy (RT) was conducted. For MOPP and RT, the CR percentage was 98% (60 of 61), and at 5 years, the percentage of patients in CR was 90%, with freedom from progression of 89% and overall survival of 91%. For TBV and RT, the CR percentage was 93% (55 of 59), with a 5-year duration of CR of 83%, freedom from progression of 81%, and overall survival of 91% (P > 0.15). The median follow-up was 65 months (range, 7 to 96 months). For 27 patients with clinical Stage IIIA, the CR percentage for MOPP and RT was 75% (12 of 16), with 1 relapse and 4 deaths. For TBV and RT, the CR percentage for clinical Stage IIIA was 73% (8 of 11) with 2 relapses and 2 deaths. Short-term toxicity except for transient leukopenia was less for TBV and RT than for MOPP and RT. Good results are achievable with combined treatment without excessive toxicity. Cancer 1992; 69:1052–1060.
[Show abstract][Hide abstract] ABSTRACT: The molecular events that allow for clonal expansion of the malignant population in chronic myelogenous leukemia (CML) are poorly understood. Recent experiments in transgenic mice suggest a close temporal relationship between expression of the aberrant protein and manifestation of a hematologic neoplasm that resembles CML; tracing the same phenomenon in humans has not been possible. We studied a patient who underwent autologous bone marrow harvest after completion of chemotherapy and radiation therapy for advanced stage Hodgkin's disease. At the time of harvest his peripheral blood counts and bone marrow were morphologically normal. Sixteen months later he developed the clinical manifestations of CML. Detailed molecular evaluation of the harvested marrow showed that a small number of cells contained the Philadelphia chromosome. The time interval required for expansion of the malignant clone, as suggested by this particular patient, was at least 16 months although it is recognized that this figure may be variable.
[Show abstract][Hide abstract] ABSTRACT: The role of adjuvant radiation therapy (RT) in the management of advanced-stage Hodgkin's disease (HD) was analyzed in 222 patients who attained a complete remission (CR) with alternating chemotherapy combinations. Mechlorethamine, vincristine, procarbazine, and prednisone/doxorubicin, bleomycin, vinblastine, and dacarbazine (MOPP/ABVD) or MOPP/ABV alternating with the lomustine, melphalan, and vindesine combination (MOPP/ABV/CAD) were similarly effective in inducing a CR in 222 of 270 (83%) patients. These patients were scheduled to receive consolidative RT to bulky disease or other critical sites of initial nodal involvement to a total dose of 2,000 cGy, with an optional additional boost of 1,000 cGy. However, only 125 (56%) patients received radiation to all initial nodal sites of disease. In 69 (31%) patients, only selected nodal sites were included in the radiation fields, and 28 (13%) did not receive any RT. Of the 222 CR patients, 42 (19%) relapsed during a median follow-up period of 6.5 years (range, 2 to 15 years). Of these, 26 (62%) patients relapsed exclusively in unirradiated nodal sites, six (14%) within irradiated sites, and 10 (24%) both within and outside irradiated fields. The actuarial 10-year relapse-free survival (RFS) and overall survival (OS) for patients receiving radiation to all initially involved nodal sites were 89% and 94%, respectively, compared with 68% and 71% (P less than .0001) for patients who had only partial or no RT. Cox proportional hazards regression analysis showed that RT to all sites of initial disease was the most significant independent covariate (P less than .005) affecting RFS and OS. These data demonstrate that residual microscopic disease is relatively frequent in patients with apparent CR after alternating combination chemotherapy, and that irradiation of all sites of initial nodal involvement decreases relapse and improves survival in advanced-stage HD.
No preview · Article · Jan 1992 · Journal of Clinical Oncology
[Show abstract][Hide abstract] ABSTRACT: The effects of transforming growth factor beta 3 (TGF-beta 3) on growth in semisolid cultures of enriched hematopoietic progenitors derived from normal human marrow and blood were evaluated. Conditioned media from the Mo-T cell line (MoCM) were the source of colony-stimulating factors used to optimally stimulate primitive progenitors. To assess whether a proportion of granulocyte/monocyte (GM) progenitors were prevented from cycling, all sizes of GM aggregates were evaluated from 3 to 20 days. The activity of TGF-beta 3 on the growth of erythroid burst-forming units (BFU-E) and granulocyte-macrophage colony-forming units (CFU-GM) was similar to that observed for TGF-beta 1. TGF-beta 3 (10, 100, and 1,000 pmol/liter), added initially or 72 h after initiation of culture, did not significantly affect the total number of marrow GM aggregates at 3, 7, 14, and 20 days, but TGF-beta 3 (1,000 pmol/liter), added initially, reduced the total number of blood GM aggregates. This suggests that some blood GM progenitors might be blocked from cycling but that the great majority of marrow GM progenitors are not blocked. Whether TGF-beta 3 (10, 100, and 1,000 pmol/liter) was added initially or after 72 h of stimulation by MoCM, there was a dose-dependent reduction of marrow and blood GM colony size even when the total number of colonies was unaffected. TGF-beta 3 (10, 100, and 1,000 pmol/liter), added initially or at 72 h, reduced in a dose-dependent manner the size of marrow and blood-derived BFU-E. TGF-beta 3 (1,000 pmol/liter) was more likely to reduce the total number of marrow and blood BFU-E, and this increased sensitivity of the erythroid lineage may prevent the development of this population in colonies derived from multipotential colony-forming unit-granulocyte/erythroid/monocyte (CFU-GEM). The results suggest that the main effect of TGF-beta 3 and TGF-beta 1 is to slow the rate of proliferation of hematopoietic progenitors rather than to prevent them from beginning proliferation. This results in a reduction in colony size which prevents the identification of primitive versus mature progenitor on the basis of standard criteria of colony size.
[Show abstract][Hide abstract] ABSTRACT: The effects of human recombinant colony-stimulating factors (r-CSFs), interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) on inducing the growth of colonies derived from patients with acute myeloid leukemia (AML) (CFU-L) were investigated and compared to the proliferative response of CFU-GM derived from highly enriched normal blast cell populations. The effects of GM-CSF and IL-3 alone were similar. Both only minimally stimulated normal colonies derived from CFU-GM when compared to stimulation with MoCM (a mean of 28% of the total colonies and 17% of the colonies greater than 100 cells obtained with MoCM). Similarly, the number of leukemic colonies was substantially less than with MoCM (less than 30% of MoCM) in all but 3/10 AML patients and both were only able to significantly stimulate CFU-L derived colonies greater than 50 cells from 2/10 patients. G-CSF alone stimulated some CFU-L derived colony growth in 9/10 patients but the number stimulated was minimal relative to MoCM in five of the patients and significant stimulation of colonies greater than 50 cells occurred in only one patient. The mean number of normal CFU-GM derived colonies stimulated by G-CSF was 41% of the total colonies and 34% of the colonies greater than 100 cells generated by MoCM. The combination of G-CSF with GM-CSF and G-CSF with IL-3 resulted in a synergistic or additive increase in the number of CFU-L in 5/10 and 7/10 patients, respectively, and a synergistic increase in the size of CFU-L in 5/10. The same combinations resulted in a significant synergistic effect on size of normal CFU-GM derived colonies. There was no evidence of a synergistic increase in the number or size of CFU-L and CFU-GM derived colonies stimulated with GM-CSF in combination with IL-3. In addition, a combination of all three (G-CSF + GM-CSF + IL-3) did not enhance the effect of G-CSF + GM-CSF or G-CSF + IL-3. These results suggest that there is significant heterogeneity among AML patients in the pattern of responsiveness of the leukemic cells to the recombinant growth factors. In addition, their responsiveness does not significantly differ from that of normal progenitors. In view of the current clinical trials with r-CSFs and cytotoxic drugs in AML patients, this issue is important and worthy of further investigation.(ABSTRACT TRUNCATED AT 400 WORDS)