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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Numerical and structural chromosome aberrations are frequently found in neoplastic cells. As demonstrated by the new chromosome banding techniques these aberrations are not random, but tend to show a specific occurrence. A model example is the leukemias where many cytogenetical investigations have been done to date. In leukemia chromosome analysis serves the following purposes: to identify a neoplastic process, to confirm and strengthen the hematological diagnosis, for the early diagnosis of transformation from a chronic leukemia into its blastic phase and for following up the clonal evolution of a leukemic cell line. In the discussion of chromosomes and neoplasms it must be mentioned that individuals demonstrating chromosomal instability and some trisomic patients show a greater tendency toward the development of a malignancy. Malignancy is primarily a cellular phenomenon caused by a disturbance in cellular regulation, whose fine events are not known. Therefore the exact role of the chromosomes in neoplastic processes cannot be stated. From experimental investigations it appears that the affected chromosomes carry cell growth regulating factors and also that a specific aberration is the result of the action of a specific agent.
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PMID:Editorial: Chromosomes and human neoplasms. Achievements using new staining techniques. 6 Feb 37

Human B cell lymphoma and murine T cell leukemia can be initiated by several agents. The present paper formulates some thoughts on the role of cytogenetic changes in the subsequent neoplastic process. Initiation creates long-lived preneoplastic cells. In some respects, they are comparable to in vitro-transformed ("immortalized") cell lines that maintain a diploid karyotype and are not tumorigenic in vivo. The development of a tumorigenic ("autonomous") clone is dependent on additional changes at the genetic level. In human B and murine T cell lymphoma, there are characteristic nonrandom chromosomal changes. The 14q+ marker appears to play a key role in human B cell lymphomas. The reciprocal 8;14 translocation in Burkitt lymphoma is a specialized subclass within this category. In murine T cell leukemia, trisomy 15 is the predominant change. The clustering of these nonrandom changes to tumors derived from a certain cell type rather than to tumors induced by a given etiological agent has important implications for the understanding of the genetic control of cellular responsiveness to growth-regulating forces in vivo.
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PMID:Lymphoma development in mice and humans: diversity of initiation is followed by convergent cytogenetic evolution. 22 25

A transplantable hamster lymphocytic neoplasma of probable monoclonal derivation, induced by the oncogenic DNA simian virus 40, has been adapted to grow in the allogeneic host either as leukemia (characterized by dissemination and poor prognosis) or as lymphoma (characterized by localization and favorable prognosis) [Diamandopoulos, G. Th. (1978) Proc. Natl. Acad. Sci. USA 75, 2011-2015]. In the present experiments the circumstances under which neoplastic lymphocytes that are transplanted in allogeneic animals retain, lose, or regain the capacity for dissemination or localization are assessed. Results indicate that the in vivo behavior of neoplastic lymphocytes is not a stable, irreversible characteristic that is transmitted to the cell progeny. On the contrary, it can be altered by the origin/tissue microenvironment in which the cells proliferate. It is suggested that, whereas neoplastic cell mutation followed by host selection could be responsible for changes in cell behavior, a more likely explanation is that the proliferating neoplastic lymphocytes acquire reversible nonmutational phenotypic characteristics during their interaction with the host microenvironment, which modify their behavior and, as a result, the prognosis of the neoplastic process.
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PMID:Microenvironmental influences on the in vivo behavior of neoplastic lymphocytes. 23 May 11

Twenty-one patients with advanced cancer or leukemia were treated with antineoplaston A and followed for up to nine months. Dosage by intravenous, intramuscular, subcutaneous, rectal, intrapleural, intravesical and/or topical administration ranged from 0.6 to 33 U/m2/24 h. Treatment was well tolerated, although side effects included fever of short duration and elevation of platelet and white blood count. In 18 cases some degree of clinical improvement was observed. Complete remission occurred in 4 cases. More than 50% remission occurred in 4 other cases which, along with another 6 cases, are continuing the treatment with high doses of antineoplaston A and show a continuing regression of the tumors although not yet achieving the criteria for complete remission; 2 of these 6 cases seem unlikely to achieve remission. Two patients temporarily discontinued treatment. During treatment, 5 patients expired; in 2 of them, however, was seen significant regression of the neoplastic process. The deaths were not due to cancer or to any toxicity incurred by the treatment.
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PMID:Antineoplaston A in cancer therapy. (I). 27 68

Sixty-one cases of the Zollinger-Ellison syndrome, encountered over a 2-year period, have been treated with cimetidine, half of them for over 1 year. Two-thirds of the patients responded to 300 mg of the drug every 6 hr by mouth. Others required up to 600 mg every 6 hr. In adequate doses the drug was highly effective: it controlled pain and dyspepsia, restored weight, abolished diarrhea, and allowed healing of ulcers and other inflammatory conditions. Missed or reduced doses led to rapid return of symptoms. Progression of the basic neoplastic process, with associated secretory drive, was unimpeded. Patient acceptance of the drug was 100 percent, and apart from minor transient abnormalities, gynecomastia (5 cases) and liver dysfunction (3 cases), which resolved while treatment continued, no serious adverse effects were seen. Of 61 patients 48 are still on the drug, 3 who were well controlled were treated surgically, 5 died for reasons unrelated to therapy, and 5 had significant problems. The drug provides an alternative to total gastrectomy and can be recommended with confidence for the suitably selected patients. The drug was also beneficial in some cases of the short bowel syndrome, systemic mastocytosis, and endogenous hyperhistaminemia due to leukemia.
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PMID:Report on the United States experience with cimetidine in Zollinger-Ellision syndrome and other hypersecretory states. 62 Sep 13

Hypophysectomy of rats bearing 7,12-dimethylbenzanthracene-induced leukemia has been reported to result in a prompt and persistent regression of the leukemia. The purpose of this study was to determine whether or not marked alterations in prolactin secretion would influence this neoplastic process. To determine this, immature male and female Long-Evans rats were divided into three groups: Group 1, controls; Group 2, pituitary grafted (hyperprolactinemia); and Group 3, 2-bromo-alpha-ergocryptine-treated (hypoprolactinemia). Two weeks after the initial treatment and at 2-week intervals thereafter (6 total), each rat was given a single intragastric intubation of 7,12-dimethylbenzanthracene (10 mg/rat). Two months after the initial carcinogen treatment and at 2- to 3-week intervals thereafter, all rats had liver biopsies for the identification of leukemia. Results clearly show that despite nearly 10-fold difference in mean serum prolactin levels in the three groups of female rats and nearly a 20-fold difference in the level of this hormone in male rats, no significant differences in the magnitude of this leukemogenic process could be detected. Thus, striking changes in prolactin secretion do not appear to influence significantly this leukemogenic process.
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PMID:Influence of prolactin on carcinogen-induced leukemogenesis in Long-Evans rats. 81 55

A case of chronic granulocytic leukemia was diagnosed in a ten year old miniature poodle and was observed for four and one half years. Methods of diagnosis and characteristic features are described. A persistent granulocytosis with a preponderance of mature forms and the absence of a detectable underlying pyogenic process were key diagnostic features which enabled distinction of this neoplastic process from acute granylocytic leukemia and a leukemoid reaction. Other features included dysplastic granulocytes in various developmental stages, marginal anemia and hyperplastic bone marrow (myeloid elements). No blast crisis occurred. This dog was euthanatized in August 1975.
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PMID:A case of chronic granulocytic leukemia in a dog. 106 1

The mechanisms of haemopoietic cellular proliferation are more clearly understood when the granylocytic, monocytic and macrophagic elements of the bone marrow are studied by means of in vitro cultures. Better physiological insight into stimulating and inhibitory factors is obtained in this way. These studies are of diagnostic, therapeutic and prognostic importance in the clinical handling of myeloid leukaemia dn neutropenia. It can be accepted today that the concept of myeloid leukaemia as a neoplastic process with an increased production of autonomous cell populations is to a large extent outdated, and these cells can be induced in vitro to differentiate into mature polymorphs. In the past it has been demonstrated that in vitro successes are followed by in vivo results, and in particular it is hoped that with the development of techniques for concentration of colony-stimulating factor, that this might be of therapeutic advantage in selected leukaemia patients in the future.
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PMID:[Myelopoiesis--a kinetic approach]. 108 Aug 85

Cytogenetic studies have been carried out on bone marrow aspirates from 25 patients with myelomatosis. Abnormal stem lines were present in 7 of the patients; the remainder had a diploid chromosome complement. In most patients - also in those without an abnormal clone - some metaphases had a blurred appearance similar to that seen in bone marrow aspirates from patients with acute leukaemia. In many of the chromosome preparations obtained before cytostatic therapy some metaphases with structural aberrations on the chromosomes were seen. Evidence is presented that in the patients with abnormal stem lines in the bone marrow, the chromosome abnormalities are confined to the myeloma cells and are not found in the erythrocytic or granulocytic precursors, which thus do not seem to be involved by the neoplastic process. Based on the present resuts and on a review of the relevant literature some general cytogenetic features are emphasized which may contribute to a better understainding of the disorder. Especially, it is demonstrated that in myelomatosis the cytogenetic changes are much more uniform than in other malignant disorders with the exception of chronic myeloid leukaemia.
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PMID:Cytogenetic studies in myelomatosis. 114 23

Acute leukemias are characterized by acquired genetic rearrangements that, in most cases, can be detected by cytogenetic methods as clonal chromosomal abnormalities. Whereas primary abnormalities contribute to the establishment of the leukemia and often are seen as solitary changes, secondary aberrations accrue during clonal evolution. Both abnormalities are nonrandom in distribution. The pattern differs between acute lymphocytic leukemia (ALL) and acute nonlymphocytic leukemia (ANLL) and from subtype to subtype. Some abnormalities are so characteristic as to be virtually pathognomonic for particular types of leukemia. The importance of cytogenetic characterization of leukemias is thus two-fold. First, the recurrent aberrations provide insight into the pathogenetic mechanisms that are operative. They pinpoint areas of the human genome that carry genes or regulatory sequences whose function is disrupted in neoplastic cells. Second, even before the long-term goal of a more fundamental understanding of the neoplastic process is reached, the cytogenetic aberrations have direct clinical importance. The finding of an acquired clonal chromosomal abnormality in hematopoietic cells identifies the presence of a neoplastic disease. The aberration profile may reveal whether the patient has ALL or ANLL and which subtype it is. Remission and relapse can be monitored by cytogenetic analyses. Finally, the karyotypic pattern is an independent prognostic parameter that should be considered when the choice of therapy is made.
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PMID:Cytogenetic analysis in the diagnosis of acute leukemia. 151 24


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