Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “malignant transformation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1998

Teratoma with malignant transformation: diverse malignant histologies arising in men with germ cell tumors.

PURPOSE: Teratoma with malignant transformation refers to a form of germ cell tumor in which a somatic teratomatous component becomes morphologically malignant and develops aggressive growth. We evaluated the spectrum of histologies, chromosomal abnormalities and clinical outcome in patients with teratoma with malignant transformation. MATERIALS AND METHODS: We identified 46 patients with germ cell tumor meeting morphologic criteria for malignant transformation. Histology, disease extent and treatment were correlated with survival. Tumors in 12 patients were studied by conventional cytogenetics or molecular genetic techniques for the isochromosome 12p [i(12p)], a marker for germ cell tumor, as well as other chromosomal abnormalities. RESULTS: The site of first detection of malignant transformation occurred in the primary tumor of 21 cases (44%), at a metastatic site in 20 (43%) and in both sites in 5 (10%). Sarcoma was the most frequent histology, identified in 29 patients (63%) with rhabdomyosarcoma the most common subtype. Seventeen tumors (37%) contained a solid tumor histology other than sarcoma, with adenocarcinoma and primitive neuroectodermal tumor as the most common histologies. Four patients with mediastinal germ cell tumor containing sarcoma also had hematological malignancies, including a focus of nonHodgkin's lymphoma in the mediastinal primary tumor (1) and nonlymphocytic leukemia in spleen or bone marrow (3). Patients who had teratoma with malignant transformation components confined to the testis or retroperitoneum completely resected experienced a longer survival than those with distant metastases or incompletely resected tumors (p = 0.003). Chromosomal abnormalities associated with germ cell tumor (i[12p]) were identified in 11 of 12 tumors containing adenocarcinoma, primitive neuroectodermal tumor, sarcoma and leukemia. In addition to i (12p), chromosomal rearrangements characteristic of the transformed histology were detected in 4 tumors. CONCLUSIONS: A variety of nongerm cell histologies, including sarcoma, adenocarcinoma, primitive neuroectodermal tumor and leukemia, may occur in association with germ cell tumor. Chromosomal abnormalities in these tumors include i (12p), reflecting germ cell tumor clonality, as well as chromosomal abnormalities associated with the transformed histology. These tumors do not respond like germ cell tumor to cisplatin-containing chemotherapy regimens. Treatment should be tailored according to that used in standard management of the transformed histology, and surgical resection is the mainstay of therapy.

Adenocarcinoma↗
PubMed2026

Viral mimicry escape as a necessary feature of malignant transformation.

Malignant transformation is driven by disruption of pathways regulating proliferation and cell fate, but these same disruptions can create a collateral vulnerability: loss of transcriptional and epigenetic control over transposable elements and other normally silenced genomic regions. Consequently, emerging cancer cells can accumulate transposable element-derived and other endogenous immunogenic nucleic acids capable of triggering antiviral responses, a process termed viral mimicry. Increasing evidence indicates that viral mimicry can eliminate precancerous cells and shape tumour evolution, positioning it as an intrinsic tumour-suppressive mechanism. Here we highlight how cancer-associated changes in DNA methylation, histone modifications, splicing and RNA processing can lead to the presence of immunogenic nucleic acids that can activate viral mimicry pathways. We outline how cancer cells suppress viral mimicry, including compensatory epigenetic repression, RNA editing, nucleic acid decay and dampening of interferon signalling to enable cancer cell growth. Finally, we highlight the evidence suggesting that escaping viral mimicry is a fundamental process for cancer initiation and progression, and suggest that viral mimicry escape is necessary for cancer transformation and a therapeutic target in combination with immunotherapies. By framing viral mimicry escape as a necessary part of cancer transformation, this Review provides a unifying conceptual model for its translational exploitation.

Journal Article↗
PubMed1991

Human immunodeficiency virus induction of malignant transformation in human B lymphocytes.

Aggressive B-cell lymphomas are occurring with increasing incidence among individuals infected with human immunodeficiency virus (HIV). Several lines of evidence implicate both Epstein-Barr virus (EBV) and c-myc activation in the pathogenesis of a major subset of these tumors. These observations prompted our investigation of interactions among EBV, c-myc, and HIV in primary B cells. We show that nonimmortalized peripheral B lymphocytes from EBV-seropositive, HIV-seronegative donors can be infected by HIV and that a subset of these lymphocytes become transformed. Malignant transformation was documented by several criteria. These cells displayed altered growth properties, propagating in 1% serum and cloning in soft agar, and formed invasive tumors of Burkitt lymphoma phenotype after subcutaneous injection into severe combined immunodeficiency mice. Such cells revealed marked enhancement of EBV DNA and RNA and of endogenous c-myc transcripts and protein. HIV-1 infection of already immortalized B-cell lines led to a similar upregulation of EBV and c-myc transcripts. These data indicate that HIV has properties of a transforming retrovirus, as it mediates two events linked to B-cell neoplasia: deregulation of c-myc and activation of EBV. They also raise the possibility of a role for HIV, apart from induction of immune suppression, in the pathogenesis of B-cell lymphoma in the acquired immune deficiency syndrome.

Animals↗
PubMed1975

1-beta-D-arabinofuranosylcytosine-induced malignant transformation of hamster and rat cells in culture.

The potent antileukemic chemotherapeutic drug, 1-beta-D-arabinofuranosylcytosine (ara-C), was observed to transform malignantly secondary hamster fetal cells as well as established rat cells in vitro. Results indicated that: (a) hamster cells altered by treatment with ara-C are morphologically indistinguishable from cells transformed with benzo(a)pyrene; (b) the ara-C-induced transformation can be observed under conditions of little or no inhibition of DNA synthesis and little or no cytotoxicity; (c) the transformation can occur with only a 6-hr exposure to ara-C; and (d) the transformation of hamster cells seems to require cellular DNA synthesis for cells in S phase are much more sensitive to ara-C-induced transformation than are G1-arrested cells. Representative transformed colonies of hamster and rat cells produced rapidly growing fibrosarcomas in inoculated newborn hamsters and rats, respectively. Control cells remained nontumorigenic.

Animals↗
PubMed1975

Plasma membrane alteration associated with malignant transformation in culture.

The intramembrane organization of the plasma membranes of nonmalignant cells in culture has been compared by freeze-fracturing with that of virally-transformed malignant cells. No dramatic differences are present in the distribution of intramembrane particles in the plasma membranes of these cells when the cells are examined without fixation or with mild fixation (glutaraldehyde treatment) prior to freezing. However, a redistribution of intramembrane particles into aggregates occurs in the membranes of nontransformed cells after treatment with glycerol. The aggregation of particles is extensive in normal chick embryo fibroblasts, and less extensive in mouse 3T3 cells. The glycerol-induced particle redistribution is not inhibited at 4 degrees, but it is inhibited by pretreatment with 2.5% glutaraldehyde. A significant number of the cells remain viable after the glycerol treatment, and the process is reversible. Particle aggregation does not appear to be related to either growth rate or cell density. Transformed Rous sarcoma virus/chick embryo fibroblasts and simian virus 40/3T3 cells have few particle aggregates after glycerol treatment. The plasma membranes of chick embryo fibroblasts transformed with a mutant of Rous sarcoma virus (TS-68) that is temperature sensitive for transformation, have few particle aggregates when grown at the permissive temperature (37 degrees). Extremely prominent particle aggregates are present in the plasma membranes of cells grown at the nonpermissive temperature (41 degrees). These observations indicate that there is an alteration in the plasma membrane associated with viral transformation which is related to a glycerol-sensitive mechanism that controls the distribution of intramembrane particles.

Animals↗
PubMed1990

Malignant transformation of human fibroblasts by oncogene transfection or carcinogen treatment.

Exposure to chemical carcinogens or radiation is considered to cause most human cancer, but human cells in culture have not been successfully transformed to malignancy by such agents. Malignant transformation is a multi-step process and one explanation for the failure to induce such transformation of human cells in culture could be inability to recognize the phenotypes of carcinogen-treated cells that have undergone intermediate changes, so that these cells can be isolated and exposed a second time to cause further changes. To identify possible intermediates, we transfected diploid human fibroblasts with oncogenes known to be active in cells derived from fibrosarcomas and determined the phenotypes produced. H- or N-ras oncogenes flanked by suitable enhancer and promoter sequences caused the cells to exhibit several characteristics of malignant cells, but not to acquire an infinite life span or form tumors. Transfection of these oncogenes in the same constructions, or a viral K-ras oncogene, into an infinite life span, near-diploid, non-tumorigenic cell strain developed in this laboratory (MSU-1.1 cells) resulted in distinct foci of morphologically-altered, anchorage independent, and growth factor independent cells that formed progressively-growing, invasive malignant sarcomas in athymic mice and expressed the p21s of the transfected ras genes. Transfection of two other infinite life span human cell lines with the H-ras oncogene in the same construction also yielded malignant cells. Recently, we succeeded in inducing the malignant state in MSU-1.1 cells using carcinogen identified that are one step removed from malignant transformation, others that are two-steps removed, etc. Furthermore, we know what new phenotypes these cells need to express to be malignantly transformed and which oncogenes can make such a change. If, as suggested above, proto-oncogenes are the cellular targets for carcinogen attack, it should be possible, by carcinogen treatment to bring about the malignant state. We have recently succeeded in achieving just such transformation by exposing MSU-1.1 cells to chemical carcinogens.

Animals↗
PubMed1995

Over-expression of p53 protein as an indicator of the malignant transformation in spiradenoma.

Malignant spiradenomas (spiradenocarcinomas) are exceedingly rare tumours of cutaneous adnexal origin, consisting of two components: benign--the pre-existent adenoma, and malignant--developing from the former part. We studied p53 protein expression in both compartments of three cases of malignant spiradenoma and compared these results with results obtained with eight cases of spiradenoma. Nuclear staining was consistently negative in all benign tumours, whilst in the cases of malignant transformation within spiradenoma p53 protein was present in the carcinomatous component, but the immunostaining remained negative in the benign counterpart of the tumour. In the zone of transition between both components of the spiradenocarcinomas p53 expression was positive in the cells with morphological atypia, providing clear discrimination. Thus, we conclude that the accumulation of p53 protein, which results from alterations in its turnover, accompanies the process of malignant transformation within long-standing spiradenomas.

Adenoma, Sweat Gland↗
PubMed1999

Loss of responsiveness to transforming growth factor beta induces malignant transformation of nontumorigenic rat prostate epithelial cells.

Transforming growth factor (TGF)-betas are multifunctional growth factors, the properties of which include the potent inhibition of epithelial cell growth. Expression patterns of TGF-betas and TGF-beta receptors in the normal prostate indicate that these growth regulators play key roles in prostatic development and proliferative homeostasis. Importantly, TGF-beta receptor levels are frequently diminished in malignant human prostate tissue. To test the hypothesis that loss of TGF-beta responsiveness is causally involved in the tumorigenic process, we have used retroviral transduction to introduce a dominant-negative mutant type II TGF-beta receptor (DNR) into the premalignant rat prostatic epithelial cell line, NRP-152. High-level expression of the DNR abolished the ability of TGF-beta to inhibit cell growth, to promote cell differentiation, and to induce apoptosis, and it partially blocked the induction of extracellular matrix gene expression. When injected into nude mice, NRP-152-DNR cells formed carcinomas at 13 of 34 sites, compared with 0 of 30 sites for parental and control cells (P = 0.0001). We conclude that the type II TGF-beta receptor is an important tumor suppressor in the prostate, and furthermore, that loss of TGF-beta responsiveness can contribute early in the tumorigenic process by causing the malignant transformation of preneoplastic cells.

Animals↗
PubMed1988

Malignant transformation in craniopharyngioma.

Malignant transformation in a craniopharyngioma has not been described previously. A 49-year-old woman presented with recurrence of a suprasellar craniopharyngioma diagnosed 35 years previously. The patient had been treated surgically for recurrence on five occasions. Radiation therapy had been administered 7 years before the final presentation. Tissue obtained from the fifth operation revealed malignant degeneration in a typical craniopharyngioma.

Craniopharyngioma↗
PubMed1987

Malignant transformation of eccrine tumors.

Malignant transformation occurred in pre-existing sweat gland tumors in 7 patients. Three lesions showed an histologic pattern of eccrine spiradenoma, 2 eccrine poroma, one cylindroma and one papillary eccrine adenoma. Malignant transformation was histologically characterized by the presence of solid tumor areas populated with large cells having irregularly shaped nuclei and mitotic figures. There were multiple foci of squamous metaplasia, areas of loss of basement membrane and invasion of the surrounding connective tissue.

Adenoma, Sweat Gland↗
PubMed2000

[Ulcerative colitis-associated colorectal carcinoma. DNA ploidy as indicator of impending malignant transformation?].

The onset of a malignant transformation in long-standing ulcerative colitis is difficult to predict. The value of the clinical and histomorphological parameters in current use is limited. It was thus aim of the present study to investigate the value of DNA-ploidy for the early detection of a malignant transformation in long-standing ulcerative colitis. This retrospective study comprised 20 patients with long-standing ulcerative colitis. The average observation time was 7.3 years (range: four to twelve years). All patients took part in a surveillance program and had between four and seven colonoscopies within a minimum period of time of five years. At these instances mucosal biopsies were taken in a standardized manner at eight different locations throughout the colon. These paraffin-embedded specimens (n = 542) were analyzed histomorphologically and DNA-cytometrically. During the observation time five patients developed an ulcerative colitis-associated colorectal carcinoma (UCA). In these patients epithelial dysplasias were not more common than in the remaining 15 cases. The vast majority of the specimen of the patients with UCA showed distinct DNA-cytometrical alterations, i.e. they were aneuploid. Such aneuploid mucosal cell populations were distributed over the whole colon, irrespectively of the later site of the carcinoma. These aneuploid lesions were found in one case eleven years, in an average seven years prior to the final diagnosis of a UCA. In contrast, the colon epithelium of the patients without UCA showed only proliferative-diploid DNA-distribution patterns during the observation time. In summary, affected patients had multiple highly aneuploid lesions of the colon mucosa at an average of seven years prior to the final diagnosis of UCA. These lesions came from macroscopically chronic inflamed tissue, and where histomorphologically without signs of dysplastic transformation. DNA-cytometrical investigations could thus be of additional predictive value for the individual risk assessment as regards an impending malignant transformation.

Adult↗
PubMed1993

Cutaneous cylindroma with malignant transformation.

BACKGROUND: Malignant cutaneous cylindroma is a rare tumor. It has been described in 26 cases, both in the solitary form and in the autosomal dominant inherited multiple tumor form. The authors present two new cases that occurred in one family with a history of multiple cylindromas. METHODS: Clinical and histopathologic data of both tumors were compared with those of 26 other cases in the literature. Immunohistochemical examinations were performed. RESULTS: The malignant tumors were distinguished from the benign lesions by rapid growth, long-standing ulceration, or bleeding. Histopathologic examination showed a well-differentiated carcinoma in one patient and a poorly differentiated tumor in the other. In the latter, lymph node metastasis developed, and the patient died 2.5 years later. Histopathologic criteria of malignancy included cell pleomorphism, frequent mitoses and loss of jigsaw pattern, peripheral palisading, hyaline sheaths, and dual cell population. CONCLUSIONS: These observations are in accord with those in the literature. Malignant cutaneous cylindroma developed more often in the multiple tumor form than in the single tumor form. Malignant cylindroma is an aggressive carcinoma with a tendency to local destructive growth and metastases.

Aged↗
PubMed1985

Malignant transformation in non-irradiated recurrent respiratory papillomatosis.

The clinical, radiographic and post mortem findings occurring in a 6-year-old female with a four-year history of recurrent respiratory papillomatosis (RRP) are described. At autopsy, there were two separate foci of malignant transformation (malignant degeneration) in the bronchioloalveolar papillomata. This patient is the youngest in whom such changes have been described. Malignant transformation is a rare occurrence and is usually seen in older patients with longstanding papillomatosis, therapeutic irradiation, or a history of smoking. Pulmonary spread represents the majority of cases with "spontaneous" malignant transformation.

Age Factors↗
PubMed1999

Malignant transformation of neurofibromas in neurofibromatosis 1 is associated with CDKN2A/p16 inactivation.

Patients with neurofibromatosis 1 (NF1) are predisposed to develop multiple neurofibromas (NFs) and are at risk for transformation of NFs to malignant peripheral nerve sheath tumors (MPNSTs). Little is known, however, about the biological events involved in the malignant transformation of NFs. We examined the CDKN2A/p16 gene and p16 protein in NFs and MPNSTs from patients with NF1. On immunohistochemical analysis, all NFs expressed p16 protein. The MPNSTs, however, were essentially immunonegative for p16, with striking transitions in cases that contained both benign and malignant elements. None of the benign tumors had CDKN2A/p16 deletions, whereas three of six MPNSTs appeared to have homozygous CDKN2A/p16 deletions. Methylation analysis and mutation analysis of CDKN2A/p16 in MPNSTs did not reveal any abnormalities. These results show that malignant transformation of NF is associated with loss of p16 expression, which is often secondary to homozygous deletion of the CDKN2A/p16 gene. The findings suggest that CDKN2A/p16 inactivation occurs during the malignant transformation of NFs in NF1 patients and raises the possibility that p16 immunohistochemistry may provide ancillary information in the distinction of NF from MPNST.

Adolescent↗
PubMed1998

Prognostic features of teratomas with malignant transformation: a clinicopathological study of 21 cases.

PURPOSE: Teratomas with malignant transformation comprise up to 6% of metastatic teratomas. The prognosis of patients with these tumors can vary considerably. We delineate factors that may be related to prognosis in a cohort of men with teratoma with malignant transformation. MATERIALS AND METHODS: We analyzed pathological features, treatment, response, recurrence, time to recurrence, subsequent followup and survival for 21 patients (median age 28 years) diagnosed with teratoma with malignant transformation during a 7-year period at our institution. RESULTS: Malignant nongerm cell elements were present in the primary tumor in 11 cases (52%). Of 18 patients with testicular primaries 17 (94%) presented with metastatic disease. Despite aggressive treatment with surgery and chemotherapy 17 of 21 cases (81%) recurred (median time 6 months). Overall, 5 patients (24%) died of disease (median survival 23 months), 5 (24%) are alive with metastases (median followup 41 months) and 11 (52%) have no evidence of disease (median followup 50 months). Progression/recurrence was substantially greater for 2 of 2 cases with a mediastinal origin, 3 of 4 with rhabdomyosarcomatous differentiation and 5 of 6 with neural differentiation compared with the remainder of the cohort (p < 0.05). CONCLUSIONS: Teratomas with malignant transformation are usually metastatic at presentation, have a high recurrence rate and are more aggressive than teratomas without malignant transformation. Prognosis is especially poor for mediastinal teratomas with malignant transformation and for those with neural or rhabdomyosarcomatous differentiation. Complete surgical resection of residual or recurrent disease appears to offer the best chance for prolonged survival.

Adolescent↗
PubMedDate not supplied

Malignant transformation of plantar ulcers in leprosy.

Malignant transformation of plantar ulcers in leprosy is not uncommon. The apparent rarity of these neoplasms could be because many observed cases are not reported. To determine the extent of the problem, 133 consecutive cases of plantar ulcers seen over two years were studied clinically as well as histologically. Plantar ulcers were more common in the distal third of foot (64.67%) but malignant transformation was seen more often in plantar ulcers of proximal third of foot (64.29%). Malignant transformation was more common in plantar ulcers of long duration. Histologically, most of the lesions were benign, being instances of pseudo-epitheliomatous hyperplasia (57.89%) or atypical pseudo-epitheliomatous hyperplasia (13.53%). However, squamous cell carcinoma was observed in 10.53% cases. Thus it may be that more cases with this complication will be detected if it is borne in mind that malignant change may be encountered in such ulcers.

Biopsy↗