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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There is abundant evidence that leukemia arise through somatically acquired genetic changes. Familial or congenital predisposition is rarely involved. These genetic changes are often visible as chromosomal aberrations. Molecular analyses of the DNA sequences rearranged in leukemia has demonstrated the presence of cellular oncogenes which are modified (fused, mutated, truncated) by the specific translocations. This results in a disturbance of the delicate balance between proliferation and differentiation and constitute a major step towards cell transformation. Some of these genetic rearrangements have been analyzed in depth, but the exact defect that causes leukemia is often not yet understood. Meanwhile these studies have increased our knowledge of normal cell proliferation and differentiation and provided us with new tools for diagnosis and for developing more specifically targeted treatment. An example would be the production of antibodies that recognize specifically the new chimeric proteins. Oncogenesis is a complex and multiple step process that proceeds by acquisition of successive genetic insults. The different steps do not necessarily occurs following a predetermined order, although some secondary changes are preferentially induced by a given first mutation. In leukemia, sequential changes in karyotype are well documented but molecular makers for tumor progression have not yet been systematically investigated. This is one of our many challenges for the future.
Leukemia 1992 Nov
PMID:Cytogenetics and oncogenes. 143 20

A human multiple myeloma (MM) cell line, U-266, has developed the ability to grow independently of exogenous interleukin 6 (IL-6) during long-term cultivation in vitro. The early passage, feeder-cell dependent U-266 cell line (U-266-1970) was compared with the late passage U-266-1984 cell line with respect to response to IL-6, IL-1 beta and tumour necrosis factor alpha and expression of IL-6 and IL-6 receptor (IL-6R) mRNA and protein. The results showed that; (a) only the U-266-1970 cell line was stimulated to growth by IL-6, (b) IL-6 and IL-6R mRNA were expressed in both cell lines, (c) the level of IL-6 mRNA was increased in the U-266-1984 cell line and only this line produced IL-6 and, (d) the level of IL-6R mRNA was highest in the U-266-1984 cell line and the number of IL-6R about ten times higher than in U-266-1970. The growth of the IL-6-producing U-266-1984 cell line was inhibited by 30% by anti-IL-6R antibodies suggesting the possibility that an autocrine IL-6 loop might have developed during the long-term cultivation. In addition to many other phenotypic alterations of the U-266 cell line, having developed as a consequence of tumor progression in vitro, its growth factor requirement seems to have evolved from a dependence on IL-6 as a paracrine growth factor to a capacity for autonomous growth, dependent on autocrine IL-6 stimulation. Whether such a development also may take place in MM clones in vivo remains to be established.
Leukemia 1992 Apr
PMID:Increase in interleukin 6 (IL-6) and IL-6 receptor expression in a human multiple myeloma cell line, U-266, during long-term in vitro culture and the development of a possible autocrine IL-6 loop. 158 93

The in vivo role of LFA-1 molecule in the immune reaction to a murine retrovirus-induced tumor was investigated. Local and systemic treatment with high doses of anti-LFA-1 monoclonal antibody led to tumor progression by blocking CTL interaction with tumor cells without interfering with CTL generation and localization in the tumor mass.
Leukemia 1992
PMID:The in vivo role of leukocyte function-associated antigen-1 in cytotoxic cell activity against tumors induced by Moloney-murine sarcoma/leukemia retroviral complex. 160 16

It has been suggested that circulating immune complexes (CIC) favor tumor progression by suppressing the host's immune response to malignant cells via blocking factors to cell-mediated cytotoxicity. We prospectively measured CIC by the C1q binding assay in 100 untreated patients with acute myeloid leukemia (AML) de novo. The median CIC level was 135, the range 0-1000, and the mean +/- standard error (SE) 175 +/- 18 micrograms/ml. Sixty-eight patients, termed abnormal, had C1q binding levels greater than 2SE above the mean of the normal population (61 +/- 15 micrograms/ml). There were no significant differences between the 32 patients with normal CIC and the 68 with abnormally elevated CIC in any pretreatment characteristic: gender, age, white blood cell count (WBC), platelets, leukemia cell mass, LDH, immunoglobulins, or fibrinogen. Abnormal CIC levels did not correlate with FAB morphology, the presence of a clonal chromosomal abnormality (76% of all patients), or with specific cytogenetic subgroups, although nine of 11 patients with acute promyelocytic leukemia and t(15;17) had abnormal CIC. There were no significant differences in complete remission (CR) rates after the first chemotherapy course (45 vs 40% for normal vs abnormal CIC) or after all courses of treatment (55 vs 65%). Survival from diagnosis was not significantly different for the normal and abnormal groups (9.3 vs 5.8 months, p = 0.24), but survival after achieving a CR was markedly longer for those with normal pretreatment CIC (33.8 vs 11.7 months, p = 0.0068). Pretreatment CIC strongly correlated with remission duration for the 59 patients who achieved CR (16.5 months for 17 normal patients vs 6.9 months for 42 abnormal patients, p = 0.0002). This was independent of age, WBC, leukemia cell mass, or FAB morphology. Within the lowest C1q quartile (less than 60 micrograms/ml), 43% of the patients have not relapsed with a minimum follow-up of 18 months compared to only 6-14% for the three higher quartiles. We conclude that host immunity as assessed by CIC levels has little effect on the initial response to therapy but may play a role in maintaining remission in AML.
Leukemia 1991 Feb
PMID:Circulating immune complexes correlate with remission duration in acute myeloid leukemia. 202 Jan 95

We have reviewed literature data on 6,306 cases of hematological neoplasia--acute and chronic lymphatic and myeloid leukemias (CML excepted), myelodysplastic and chronic lymphoproliferative and myeloproliferative disorders, and malignant lymphomas--with the goal of quantitatively ascertaining how often cytogenetically unrelated clones occur in these diseases. Unexpectedly wide variations were found: in ANLL, unrelated clones were present in 1.1% of the 2,506 known cases with chromosome abnormalities characterized with banding technique; in the various myelodysplastic (MDS) and chronic myeloproliferative (CMD) disorders (total number of cases 1,299) the frequency was 4.3% and in lymphatic malignancies 1.3% (total case number 2,501). In the latter group the proportions varied between 0.4% and 0.6% in ALL and malignant lymphoma (ML) to as much as 6.2% in CLD and 7.3% in CLL. Some karyotypic abnormalities were encountered more often than would be expected from their general frequency in the various diseases. This discrepancy was particularly evident in MDS and CMD, where 5q- was found in slightly less and +8 in somewhat more than half of the 56 cases. Furthermore, these two aberrations were found as the only changes in the two coexisting clones in one-fourth of the material. Although if viewed in isolation these data would undoubtedly be best explained by assuming a multicellular origin of the neoplasm, it is entirely possible that what are cytogenetically perceived as unrelated clones could be subclones with some invisible aberration in common. If so, this interpretation indicates that changes like +8 and 5q-, both of which are common rearrangements in bone marrow neoplasms, are actually secondary changes that develop during tumor progression.
Leukemia 1989 Jan
PMID:Cytogenetically unrelated clones in hematological neoplasms. 290 9

Chromosomal changes such as aneuploidies, translocations, and gene amplification occur in many murine tumors. In this study, we have analyzed the changes in chromosomes at different stages of tumor development in C57BL/6J mice treated with gamma-irradiation or the chemical carcinogen, N-methylnitrosourea. Trisomy 15 occurred in both groups of mice regardless of inducing agent. The frequency of this event differed significantly in radiation-treated animals between stage I and stage II of the disease. A specific marker chromosome occurred only in the gamma-irradiated mice and not in the mice treated with N-methylnitrosourea. This marker consists of a translocation between chromosomes 1 and 5. It occurred in 43% of the gamma-irradiated animals at stage 1 of the disease and did not vary markedly during tumor development. In contrast, trisomy 15 increased in frequency between stages I and II of the disease in the same animals. These results suggest that the translocation event may be an early event in tumor development, whereas trisomy 15 may contribute to tumor progression.
Leukemia 1988 Feb
PMID:Identification of a specific marker chromosome early in tumor development in gamma-irradiated C57BL/6J mice. 325 3

About half of the patients with follicular lymphoma will develop an aggressive B cell lymphoma with morphological changes in growth pattern and cellular morphology. Changes of the immunophenotype, especially of the expression of immunoglobulin (Ig) have been documented less frequently. Multiple tumor samples of two patients with follicular lymphoma who developed tumor progression, were studied by Southern blot analysis for rearrangements of the Ig genes and the oncogenes BCL2 and MYC. In both patients, the general pattern of Ig gene rearrangements, especially of the Ig light-chain genes, and the structure of the t(14;18) breakpoint as assessed by the polymerase chain reaction (PRC) and fine restriction mapping, remained unaltered with time. However, both within the functional Ig heavy-chain allele and around the t(14;18) breakpoint, extensive secondary alterations took place. This indicates clonal evolution rather than the appearance of an independent lymphoma. In the first case with progression from follicular lymphoma to Burkitt's lymphoma 3 years after diagnosis, alterations were especially present 3' of the t(14;18) breakpoint. In the second patient with a change from follicular to diffuse centroblastic lymphoma 4 years after diagnosis, subsequent class switches from IgM to IgG and to defective IgH expression were accompanied by deletion of C mu sequences and a rearrangement of the MYC gene, respectively. Additionally, in both patients alterations in individual restriction sites occurred, which most likely were due to somatic mutations within both the functional IgH and translocated allele. Our data indicate that complex alterations of both the functional and non-functional IgH allele may accompany tumor progression and may erroneously suggest the appearance of independent clones by Southern blot analysis. It remains to be established whether these alterations are causative events or the consequence of genetic instability and clonal evolution.
Leukemia 1995 Oct
PMID:Histological conversion of follicular lymphoma with structural alterations of t(14;18) and immunoglobin genes. 756 20

Leukemias induced with the v-abl or BCR/ABL oncogene undergo a process of tumor progression which suggests that the ABL oncogene is required but not sufficient for full transformation. In order to identify cellular changes that correlate with progression to full transformation in v-abl transformed lymphoblasts Abelson virus (A-MuLV)-infected murine bone marrow was plated over a pre-established stromal feeder layer. Shortly after A-MuLV infection, transformed lymphoblasts were poorly oncogenic, but over time, progressed in a stepwide manner to a more oncogenic state. The transformants first acquired the ability to grow efficiently in agar, but only over the feeder layer. They next progressed to efficient feeder-independent growth in liquid culture, and then to efficient feeder-independent growth in soft agar. Cell lines that reached the advanced stage of feeder-independent agar growth showed increased detection by antiphosphotyrosine Western blot of the GAP-associated p62 phosphoprotein as well as of a 55 kDa phosphoprotein while detection of the P160 v-abl phosphoprotein remained constant throughout all stages of progression. Although the identity of the p55 phosphoprotein and the mechanism by which detection of p55 and p62 phosphoproteins change on the Western blots during tumor progression are unknown, the data demonstrate that these changes strongly correlate with the stage of progression of v-abl-transformed cells and raise the possibility that these changes may play a role in tumor progression in this model.
Leukemia 1995 Jan
PMID:Increased detection of specific tyrosine phosphoproteins correlates with tumor progression of Abelson virus-infected lymphocytes. 784 13

We have investigated the involvement of tumor suppressor genes (p53 and RB1) and dominantly acting oncogenes (Ras family genes) in BCR/ABL positive and negative chronic myeloproliferative disorders (CMPD) at different stages of the disease, including 26 cases of BCR/ABL+ chronic myeloid leukemia (CML) blast crisis, 9 myelosclerosis with myeloid metaplasia, 4 polycythemia vera, 10 essential thrombocythemia, 1 juvenile CML, and 8 BCR/ABL- CML. The presence of mutations in p53 exons 5 through 9, as well as in RB1 exons 10-27 and in N-, K-, H-Ras exons 1 and 2 was tested by the PCR-Single Strand Conformation Polymorphism technique and by PCR-Direct Sequencing. In addition, Southern blot analysis was used to investigate the occurrence of gross rearrangements in the p53 gene as well as loss of heterozygosity at 17p13, the site of p53. Acute phase BCR/ABL-CMPD cases displayed a high frequency of p53 (2/7) and Ras (3/7) lesions, whereas BCR/ABL- CMPD in chronic phase displayed only germline p53 and Ras sequences. Conversely, p53 inactivation was restricted to only 1/26 cases of BCR/ABL+ CML blast crisis. No alterations in the RB1 gene were detected in any of the cases analyzed. These data indicate that p53 inactivation and/or Ras activation might play a role in acute transformation of BCR/ABL- CMPD and that the molecular mechanisms of tumor progression may be different in BCR/ABL+ versus BCR/ABL-CMPD.
Leukemia 1994 Apr
PMID:Molecular mechanisms of tumor progression in chronic myeloproliferative disorders. 815

The role of loss or inactivation of the retinoblastoma (Rb1) and p53 tumor suppressor genes in the pathogenesis of various human malignancies has been well established, yet little is known regarding plasma cell dyscrasias. In the present study, the loss of Rb1 protein expression, and the presence of Rb1 gene rearrangements as well as the presence of p53 somatic mutations (exons 5 through 9) were investigated in a panel of plasma cell dyscrasias, including 15 monoclonal gammopathies of undetermined significance (MGUS), 63 multiple myelomas (MM), and 18 plasma cell leukemias (PCL). In the same panel of cases, we established the frequency of ras oncogene mutations, the main genetic lesion associated with MM. We report that loss of Rb1 protein and p53 mutations are detectable in 34.7 and 9.8% of MM and PCL primary cases; no lesion was found in MGUS. In advanced stage MM, and PCL cases, Rb1 and p53 inactivation, as well as ras mutations were detected. Our findings show that Rb1 and p53 inactivation are associated with aggressive plasma cell dyscrasias, suggesting a role for these lesions in tumor progression rather than initiation.
Leukemia 1994 May
PMID:Inactivation of tumor suppressor genes, p53 and Rb1, in plasma cell dyscrasias. 818 33


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