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

As a part of a program directed toward the elucidation of the role of viruses in mouse and human breast cancer, a variety of immunological techniques were applied to a study of the humoral immune response of mice and of humans to their breast tumors. Tumor-bearing mice were found to produce antibodies against a complex array of tumor cell-associated antigens, including mouse mammary tumor virus (MMTV), components, heterophile and Forssman-like antigens, embryonic antigens, and possibly other tumor-associated antigens. Mice bearing MMTV-positive tumors had high titer antibodies against both viral and heterophile antigens. Tumor-free mice, whether of high or low mammary cancer strains, were remarkably free of antibodies that could label MMTV particles, although some sera contained antibodies to viral components. Patients with breast cancer also had antibodies against a variety of antigens associated with their own and homologous breast cancer cells. These antibodies reacted with heterophile, embryonic, and other tumor-associated antigens, some of which appeared to be viral. Sera of some patients with breast cancer gave positive immunofluorescence reactions with mouse mammary tumor cells grown in tissue culture and producing MMTV. Most of these reactions were due to heterophile antibodies in the sera, but a small number of sera contained antibodies apparently directed specifically toward MMTV particles, as determined by immunoperoxidase electron microscopy. Although human-mouse cross-reactions must be interpreted with caution, these data suggest that a virus putatively associated with human breast cancer is antigenically related to MMTV.
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PMID:Implications of humoral antibody in mice and humans to breast tumor and mouse mammary tumor virus-associated antigens. 17 35

In vivo and in vitro studies bearing on tumor-specific and viral-associated antigenicity of human breast carcinomas were reviewed with particular attention to the following clinical considerations: (a) breast carcinomas arise in a nonrandom fashion; (b) in situ carcinomas precede invasive breast carcinomas; (c) invasive breast carcinomas behave in a heterogeneous fashion. Microscopically demonstrable lymphoreticuloendothelial responses, skin window tests, and leukocyte migration tests all indicate that tumor-specific antigenicity develops in assoication with the early phases of mammary carcinogenesis. Such antigenicity is maximally expressed in in situ carcinomas without associated invasive breast cancer and minimally in invasive breast cancers with metastases. Immunogenic breast cancer tissues commonly contain a protein component the antigenic and physicochemical properties of which are similar to those of a protein component of murine mammary tumor virus. Advances in our understanding and control of human mammary carcinogenesis and biological behavior are dependent on the clinicopathological characterization of individual patients and their breast tissues as well as on the analytical procedures used.
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PMID:Biological considerations of tumor-specific and virus-associated antigens of human breast cancers. 17 36

A single i.m. dose of formalin-inactivated murine mammary tumor virus greatly reduces viral expression and mammary tumorigenesis in Af (tumor incidence, 39%) and RIIIf (tumor incidence, 11%) mice, which carry only endogenous, gamete-transmitted virus. In C57BL mice, 1 mug of vaccine in Freund's complete adjuvant protects against later challenge with RIII virus.
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PMID:Further immunization studies with mammary tumor virus. 17 38

Pretreatment of MTV-induced BALB/cfC3H mammary tumor cells with autologous serum results in increased spleen cell cytotoxic activity and the recruitment of previously inactive spleen cells to cytotoxic activity against the target cells. These recruiting antibodies are tumor-specific for individual tumors; pretreatment with such serum of target cells of an MTV-induced mammary tumor obtained from a different BALB/cfC3H female results in blocking of spleen cell activity. The autologous recruiting factors are active at dilutions of 1000 or more of whole serum are found in the 19S fraction after gel filtration.
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PMID:Antibody in the sera of tumor-bearing mice that mediates spleen cell cytotoxicity toward the autologous tumor. 17 66

Specific spleen cell activity in microcytotoxicity assay can be altered by pretreatment of target mammary tumor virus (MTV)-induced mammary tumor cells with serum. Serum from both BALB/cfC3H females neonatally infected with MTV and BALB/c females horizontally exposed to MTV antigens will block specific spleen cell activity against isologous mammary tumor cells. On fractionation of sera, blocking factors are localized in the 7s fraction. The 19s fraction contains recruiting factors that are not detectable in the unfractionated serum; these factors are active against isologous tumors and are thus distinct from the tumor-specific recruiting factors previously described in the sera of tumor-bearing females, which are active only against the autologous tumor. Antibodies mediating complement-dependent cell lysis are also detectable after serum fractionation.
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PMID:Complexity of factors in sera of different mice that affect MTV-induced mammary tumor cells. 17 67

Primary mammary tumor cultures of RIII, GR, DD, BALB/c, and BALB/cfC3H mice were examined for mouse mammary tumor virus (MuMTV) production. Levels of production of 12-32 mug virus protein/day/75-cm2 culture flask could be maintained for 30-50 days with daily virus harvests. The viruses from tumor cell cultures of these mouse strains contained DNA polymerase with a strong preference for Mg++ over Mn++ as the divalent cation, a characteristic of DNA polymerase of MuMTV from mouse milk. These viruses from tumor cell cultures were excellent sources of MuMTV 3H-complementary DNA (complexed to 60-70S RNA) and radioactive 60-70S RNA, sufficiently free of contaminating murine leukemia virus nucleic acids, that can be used in molecular hybridization experiments. The effects of several culture parameters on MuMTV production were also studied.
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PMID:Characterization of mouse mammary tumor viruses from primary tumor cell cultures. II. Biochemical and biophysical studies. 17 74

Early stages of mammary tumors (EMT) were induced with a combined treatment of progesterone (P) and estrone (E) in ovariectomized adult GRS/A (GR) mice, a strain of European origin and with a high incidence of mammary cancer. The mammary tumors were comparable to the pregnancy-dependent tumors of breeding females of this strain. The hormone treatment did not lead to EMT in a variety of other strains and only occasionally in the RIII an C3H strains. Treatment with P or E alone di not lead to EMT in GR mice, but treatment with the steroid compound 17 alpha-ethynyl-19-nortestosterone (ANT) did mimic the combined effe(t of P and E. Since EMT could be induced by ANT in all ovariectomized adult GR mice within 3 weeks, this tumor-induction method was suitable for analysis of the gene responsible for palpable, pregnancy-dependent mammary tumors of this strain. Another argument for the usefulness of this test for genetic analysis was the fact that, though mouse mammary tumor virus (MuMTV) of the GR strain was introduced into BALB/c and tmas mice by foster-nursing, ANT treatment did not lead to EMT. First and second backcross analyses showed that one gene was responsible for EMT induction. There was a strong (orrelation between the presence of EMT and MuMTV antigens in the mammary glands and milk of several first backcross populations between GR and other strains such as C57BL, BALB/c, DBAf, and C3Hf. This suggested that the expression of MuMTV antigens was also controlled by the EMT gene. Two types of resistance phenomena were observed. Neither type could prevent EMT after hormone treatment; however, they could delay EMT development. One resistance factor for EMT induction was noticeable and dominant in reciprocal hybrids of the GR and DBAf strains, whereas another resistance factor was detected in the backcross population only [i.e., in the C57BL X (C57BL X Gr) ba(kcross] and not in hybrids; therefore, this factor was recessive. Until now, linkage experiments with 18 markers to locate the gene for EMT induction in the map of the mouse were unsuccessful.
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PMID:Genetic analysis of mammary tumor induction and expression of mammary tumor virus antigen in hormone-treated ovariectomized GR mice. 17 79

Mitochondria isolated from spontaneous and transplanted mammary adenocarcinomas of two strains of mice were compared, by various biochemical criteria, to mitochondria from mammary glands of midpregnant or hormonally stimulated, cancer-free mice. The specific activities of several mitochondrial enzymes including cytochrome oxidase, alpha-glycerophosphate oxidase, and succinate dehydrogenase were twofold to threefold lower, whereas the activity of monoamine oxidase was two fold higher in tumor mitochondria. Malate dehydrogenase, adenylate kinase, and NADH oxidase showed similar levels of activity in tumor and midpregnant mammary gland mitochondria. In addition, mitochondrial polypeptide composition was analyzed by electrophoresis on sodium dodecyl sulfate-urea polyacrylamide gels. Midpregnant mammary gland and mammary tumor mitochondria were similar in polypeptide composition; however, several differences were observed. A high-molecular-weight polypeptide, present in mid-pregnant mammary gland mitochondria was absent from tumor mitochondria. Also, tumor mitochondria contained an additional high-molecular-weight polypeptide not found in the midpregnant mammary gland. There were numerous differences in the relative proportions of many polypeptides common to both tumor and midpregnant mammary gland mitochondria.
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PMID:Biochemical studies on mitochondria isolated from Normal and Neoplastic Tissues of the Mouse Mammary Gland. 17 82

Large-scale studies showed that antibodies previously detectable in women with proliferating mastopathy or breast cancer were directed to intracytoplasmic type-A particles (iAp) of mouse mammary tumor virus. Immunofluorescence revealed the human antibodies to be bound only by those tumors producing a certain amount of iAp clusters visible by light microscopy. The intensity of the reaction corresponded to the iAp content of every tumor tested as revealed by electron microscopy and rabbit antisera to iAp. The fluorescence patterns obtained with positive human sera were similar to those obtained with rabbit antisera specific for iAp and resembled the tissue distribution patterns of iAp inclusions stained by acid fuchsin. The reaction with human sera was entirely blocked by rabbit antisera to iAp and, less so, by rabbit or mouse antisera to B particles. The human antibody activity was exhaustively absorbed by purified iAp or purified and disrupted B particles, which indicated that the human antibodies were directed to antigenic components shared by iAp and B particles. Preliminary immunoperoxidase studies supported the assumption that the human antibodies were bound to the iAp membrane; technical details might have accounted for the finding that the human antibodies reacted with the iAp but not with B particles in situ.
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PMID:Specificity of human antibodies to intracytoplasmic type-A particles of the murine mammary tumor virus. 17 84

Estrogen and prolactin receptor concentrations were measured in 24 carcinogen-induced rat mammary tumors and correlated with the tumor response to host ovariectomy or hypophysectomy. It was found that essentially all of the tumors contained some specific estrogen receptor, and all but three contained prolactin receptor. The values for each receptor comprised a continuum from very low to relatively high concentrations, suggesting that previous considerations of hormone dependence on the basis of presence or absence of hormone receptors may be oversimplified. The concentration of each receptor tended to be lower in the hormone-independent than in the hormone-dependent tumors, but there were a number of hormone-independent tumors with higher receptor levels than some of the hormone-dependent tumors had. A better correlation of tumor response to endocrine ablation resulted from a combination of the 2 receptor levels than from either receptor concentration alone. These results suggest that there is a complex relationship between mammary tumor response to endocrine ablatin and levels of estrogen and prolactin receptors and that some tumors may be dependent upon 1 or both of these hormones for growth.
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PMID:Estrogen and prolactin receptor concentrations in rat mammary tumors and response to endocrine ablation. 17 95


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