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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A challenging aspect of lung carcinogenesis is the elucidation of the mechanisms which permit initiated bronchial epithelial cells to attain a growth advantage over normal bronchial epithelial cells, and subsequently evolve into a malignant phenotype. In this review, the effects of interactions between normal and transformed cells, and the potential role of representative extrinsic factors on cell-cell communication are discussed. Evidence is presented to show how cell injury and the effects of serum and calcium may affect morphology and communication, and tumor development. A large number of autocrine-paracrine factors (e.g., TGF beta, TGF alpha) are released by bronchial epithelial cells. These factors may inhibit or promote the proliferation of normal and transformed bronchial epithelial cells, respectively. The ability of certain injurious and tumor promoting agents (e.g., formaldehyde, TPA) to select for the transformed phenotype may involve selective cell injury, the induction of terminal differentiation and an inhibition of gap junction communication among normal BE cells.
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PMID:Intercellular communication in bronchial epithelial cells: review of evidence for a possible role in lung carcinogenesis. 220 92

Nineteen gastric carcinomas with lymphoid stroma were selected from 554 surgical cases and examined pathologically and immunohistochemically using formaldehyde-fixed, paraffin embedded materials. Most showed ulcerative lesion and 15 cases located in fundic and cardiac gland regions. They were subdivided histologically into three groups, early (group I), localized (group II) and infiltrative tumors (group III), the number of cases being 2, 10 and 7, respectively. Lymph node metastases occurred in 3 cases in group II and 6 in group III, the latter showing a significantly higher incidence. The number of carcinoembryonic antigen and CA19-9 immunoreactive tumor cells was apparently smaller in gastric carcinomas with lymphoid stroma than in ordinary gastric carcinomas. Frequent presence of alpha 1-antichymotrypsin immunoreactivity characterized the tumor cells of gastric carcinoma with lymphoid cells. Stroma cells consisted of lymphocytes, plasma cells, granulocytes and histiocytes. Of these, the greatest number examined immunohistochemically was B cells and IgG cells, followed in descending order by T cells, IgA cells and IgM cells in the order given. A variable number of lysozyme immunoreactive histiocytes were also detected in all the cases. Gastric carcinoma with lymphoid stroma might be subclassified as a separate entity, although short term follow-up study did not demonstrate a favorable prognosis for this type of gastric cancer.
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PMID:Gastric carcinoma with lymphoid stroma: pathological and immunohistochemical analysis. 222 25

The cytologic presentations of two adult-type rhabdomyomas of the soft palate are reported. Fine needle aspiration smears of the lesions contained globular tumor cells that had striations and intracytoplasmic rod-shaped inclusions. These inclusions, corresponding to hypertrophied Z bands, were pathognomonic of rhabdomyoma tissue. The cytologic diagnosis was confirmed by histologic and immunologic studies in both cases. The cytologic preparations fixed in alcohol or air dried did not show the "spiderweb cells" observed in the histologic sections of tissue fragments fixed in formaldehyde; this clearly illustrates that the morphology of the cells of this tumor depends primarily on the specimen preparation technique used. These cases suggest that aspiration cytology can establish the diagnosis of this benign tumor of striated muscle, for which total surgical removal is usually sufficient to effect a cure. The differential diagnosis is discussed in detail.
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PMID:Adult-type rhabdomyoma of the palate. Cytologic presentation of two cases with histologic and immunologic study. 234 1

In this study, 39 primary, surgically resected, pulmonary adenocarcinomas of the following cell types were investigated: 19 Clara cell, 4 bronchial-gland, 15 goblet cell, and 1 type II alveolar epithelial adenocarcinoma. They were analyzed for the expression of the glandular differentiation-associated antigen recognized by the monoclonal antibody 44-3A6. Formalin-fixed, paraffin-embedded tissue sections were immunostained using the avidinbiotin complex/peroxidase method. All of the Clara cell tumors (19/19) expressed this antigen as well as 3/4 bronchial-gland tumors, as compared to only 2/15 goblet cell tumors. The single type II pneumocyte neoplasm studied was found to express this antigen. These findings parallel our earlier observations based on cytological features, and provide supportive evidence that there may be biological differences between human pulmonary adenocarcinomas and bronchioloalveolar carcinomas.
Tumour Biol 1990
PMID:Immunohistochemical analysis of human adenocarcinomas of the lung using the monoclonal antibody 44-3A6. 237 95

Data supporting various dose-response relationships in chemical carcinogenesis are summarized. General principles are derived to explain the relationships between exposure dose, DNA adduct level, induction of genetic changes, and tumor incidence. Some mechanistic aspects of epigenetic carcinogens (stimulation of cell division and maldifferentiation) are analyzed in a similar way. In a homogeneous population, non-linearities are frequent. They are due to phenomena of induction or saturation of enzymatic activities and to the multi-step nature of carcinogenesis: if a carcinogen accelerates more than one step, the superposition of the dose-response curves for the individual steps can result in an exponential relationship. A fourth power of the dose was the maximum seen in animals (formaldehyde). At the lowest dose levels, a proportionality between dose and tumor induction is postulated independent of the mechanism of action if the carcinogen accelerates the endogenous process responsible for spontaneous tumor formation. Low-dose thresholds are expected only for situations where the carcinogen acts in a way that has no endogenous counterpart. Epidemiological studies in humans show linear dose-response curves in all but two investigations. The difference from the strongly nonlinear slopes seen in animal studies could be due to the heterogeneity of the human population: if the individual sensitivity to a carcinogen is governed by a large number of genetic and life-style factors, the non-linearities will tend to cancel each other out and the dose-response curve becomes 'quasi-linear'.
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PMID:Dose-response relationship and low dose extrapolation in chemical carcinogenesis. 238 9

Three monoclonal antibodies elicited to NIH 3T3 cells transfected with DNA from a human pancreatic adenocarcinoma cell line recognized a novel ribonucleoprotein complex. Minimally, this ribonucleoprotein complex contained a Mr 240,000 protein (by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and two RNA species with apparent sizes of 1.5 and 3.0 kilobases (by formaldehyde agarose gel electrophoresis). In addition to a cytoplasmic and nuclear subcellular localization, the RNA antigen was secreted from human tumor cell lines and NIH 3T3 cells transfected with pancreatic tumor DNA (inhibitable by monensin) and was apparently not a viral or Mycoplasma contaminant. The ribonucleoprotein antigen was detected in some normal tissues by immunoperoxidase but was not found in or secreted from in vitro cultured normal human fibroblasts, nontransfected or spontaneously transformed NIH 3T3 cells, or normal peripheral blood leukocytes.
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PMID:A novel ribonucleoprotein complex defined by monoclonal antibodies to NIH 3T3 cells transfected with human pancreatic adenocarcinoma DNA. 239 65

Lectin-binding sites in clear cell acanthoma (CCA) were studied using an avidin-biotin complex (ABC) with 9 lectins. Formaldehyde-fixed, paraffin-embedded sections of 7 CCA lesions were employed. Positive stainings, similar to those seen in normal epidermis, were observed on the cell surface in CCA with Ricinus communis agglutinin I (RCA-I), Ricinus communis agglutinin II (RCA-II), and wheat germ agglutinin (WGA). Reduced reactivities were observed with Concanavalin A (ConA) and peanut agglutinin (PNA) in CCA. In some areas of CCA lesions, faint stainings were seen with Ulex europaeus agglutinin I (UEA-I). Capability of staining with soybean agglutinin (SBA) was completely lost in the lesions. With Bandeiraea simplicifolia agglutinin II (BSA-II), cytoplasmic stain was seen in a part of upper and spinous layers in CCA lesions. Dolichos biflorus agglutinin (DBA) did not bind to either CCA or normal epidermis. These results indicate that the lectin-binding sites of proliferating cells of CCA resemble those of epidermal keratinocytes and suggest that CCA is a tumor of epidermal origin.
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PMID:Lectin-binding sites in clear cell acanthoma. 239 62

Seven cases of alveolar soft part sarcomas (ASPSs) were studied immunohistochemically for the presence of a number of differentiation markers in an attempt to define the cellular nature of this tumor. Desmin-positive tumor cells were found in three and muscle actin-positive cells in four cases when studied in formaldehyde-fixed and paraffin-embedded material. In one case studied in frozen sections, focal desmin positivity but no other intermediate filaments were found. Immunostaining for synaptophysin, a general neuroendocrine marker, was negative in all cases. All tumors were positive with a monoclonal antibody NK1C3, which consistently stains melanomas, and three cases showed significant numbers of S-100 protein-positive tumor cells, but immunostaining with HMB-45, a melanoma-specific monoclonal antibody, was negative in all cases. However, several rhabdomyosarcomas studied for NK1C3 and S-100 protein for comparison were also at least focally positive. Electron microscopic examination, performed in three cases, showed uniform paucity of all kinds of filaments in the tumor cells of ASPS, and it specifically failed to reveal any signs of smooth or striated muscle cell differentiation. Thus, the results of the present study do not unequivocally define the nature of ASPS but speak against its paraganglionic character and present evidence for muscle cell differentiation.
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PMID:Alveolar soft part sarcoma. Immunohistochemical evidence for muscle cell differentiation. 207 82

We studied alterations in the transitional mucosa of the colon in 18 cases of primary colonic adenocarcinoma (4 from the cecum; 4, the ascending colon; 5, the descending colon; 2, the sigmoid colon; and 3, the rectum). One patient had 2 separate primary tumors. Formalin-fixed, paraffin-embedded sections were studied in all cases, and tissues fixed in methacarn fixative were available in 9. Sections of tumor and transitional mucosa were compared with those of normal mucosa distant from the tumor. Sections were stained with hematoxylin-eosin, Masson's trichrome, and alcian blue at a pH of 0.9 (sulfomucin) and at a pH of 2.5 (sialomucin and sulfomucin). Immunoperoxidase stains for collagen type IV (basal lamina) were also performed. Transitional mucosa showed morphological alterations, including increase in mucosal thickness and crypt distortion. An increase in lamina propria fibrosis was noted in transitional mucosa in 3 cases. Abnormal mucin content, consisting of a predominance of sialomucin, was noted in transitional mucosa in 12 cases. In one of these, sialomucin was predominant in both transitional and normal mucosa. No alterations in the thickness of the subepithelial collagen table were noted. Collagen type IV staining was effective in demonstrating an increase in lamina propria vascularity in transitional mucosa in 11 specimens.
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PMID:Transitional mucosa of colon. A morphological, histochemical, and immunohistochemical study. 240 82

Lung tumors of various types, fixed in 4% formaldehyde-1% glutaraldehyde, were stained for keratin proteins. The results were compared with previous ultrastructural evidence of intermediate filament bundles (IFBs), presumed to be keratin. Electron and light microscopic methods were largely complimentary and the results were in agreement in 79% of cases. Light microscopy was superior for demonstrating keratinizing foci containing numerous well-developed IFBs, whereas electron microscopy was superior when keratin filaments were sparsely distributed in cells throughout a tumor. Fetal and adult bronchial specimens were also studied. Normal adult bronchus, fixed in aldehydes, was unreactive but keratin was observed in similarly fixed bronchi that showed epidermoid metaplasia and/or intraepithelial carcinoma. Keratin was demonstrated in normal adult bronchi fixed in ethanol. Keratin was not observed in fetal lung until the 14th week of gestation, when it appeared in basal cells and a few columnar cells of the larger bronchi. Thereafter, keratin progressively appeared in the more distal branches. As specimens from gestations of less than 14 weeks were fixed in aldehydes, the apparent lack of immunoreactivity may have been artifactual. Nevertheless, keratin was demonstrable in aldehyde-fixed fetal bronchi at 16 and 23 weeks' gestation.
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PMID:Immunohistochemical studies of keratin in human bronchus and lung tumors. 240 48


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