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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MHC class I antigens on tumor cells are expected to play an important role because they regulate the sensitivity to antitumoral immunological mechanisms. Overall or selective qualitative or quantitative changes in MHC molecules may modify the recognition of tumor cells by components of the immune system. It seems clear that MHC antigen expression on tumor cells is important in triggering the immune response by autologous lymphocytes. A deficiency in or lack of MHC class I antigens may have profound effects on T and NK cell activity. In experimental models, variation in the expression of MHC class I antigens has been shown to exert a decisive influence on local tumor growth and metastasis. However, there is little information about the influence of selective loss of individual locus products on the behavior of human tumor cells. Total and selective HLA losses have been found in a large variety of tumors, and different mechanisms have been shown to be responsible for these changes. In some examples, HLA losses are associated with a poor degree of tissue differentiation and poor prognosis. In other tumors, however, no such association has been found. We do not know whether HLA class II expression in neoplastic cells plays an immunological role, although, with the exception of melanoma, HLA class II expression is more frequently observed in tumors with a more favorable prognosis. Finally, there is no doubt that we need to learn more about how to manipulate the expression of MHC class I and II antigens in human tumors, in order to stimulate immune response.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:MHC antigens on human tumors. 176 5

New analogs of diflubenzuron, a benzoylphenyl urea, are tested on their in vitro cytostatic activity against B16 melanoma cells. The following structure-activity relationship was established: substitution by a hydroxylated function at the ortho, meta or para position or by a dimethylamino function at the ortho position of the benzoyl moiety appeared to be necessary for cytostatic activity in vitro. Acetoxy functions at the ortho position or hydroxy functions at the para position of the aniline ring resulted also in active compounds. A number of these benzoylphenyl ureas are selected for in vivo evaluation of antitumor activity on B16 melanoma growing s.c.. Although many of the tested benzoylphenyl ureas delayed tumor growth during the first ten days of drug treatment, only a few increased animal life span. The best results (% T/C) were obtained with compounds 5 (127%), 7 (147%), 13 (135%) and 16 (135%), which all have hydroxylated functions in the benzoyl moiety.
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PMID:Effects of benzoylphenyl ureas on growth of B16 melanoma cells in vitro and in vivo. 178 22

Previously we found that the reconstituted basement membrane matrix Matrigel, when premixed with human small-cell lung carcinoma cells and injected subcutaneously into athymic mice, permitted tumor growth, whereas cells injected in the absence of Matrigel did not form tumors. In the present study, we examined additional cell types and determined some of the underlying mechanisms involved in the promotion of tumor formation by Matrigel. The tumor cell lines that we studied included transformed mouse Englebreth-Holm-Swarm tumor cells (T-EHS), human submandibular carcinoma A253 cells, mouse melanoma B16F10 cells, human epidermoid carcinoma KB cells, and human primary renal cell carcinoma cells. When coinjected subcutaneously with Matrigel, these cell lines formed rapidly proliferating tumors. Primary biopsy specimens of human colon carcinoma, when dispersed and coinjected with Matrigel, also formed tumors. Only A253, KB, and B16F10 cells formed small tumors in the absence of Martrigel, but a fivefold to tenfold increase in tumor size was observed in the presence of Matrigel. These data demonstrate a useful method for improving the growth of human tumors in athymic mice.
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PMID:Enhanced tumor growth of both primary and established human and murine tumor cells in athymic mice after coinjection with Matrigel. 192 May

BRO human melanoma cells, encapsulated in fibrinogen clots and implanted under the subrenal capsule of immunosuppressed mice, serve as a model for evaluating the effects of chemotherapeutic agents on human tumors in vivo. Histological examination of 8-day tumors in mice which had received 4.5 Gy prior to implantation, showed that the cells were largely viable. Radiation at this dose exerted no significant additional toxicity for mice given therapeutic doses of anticancer drugs. Effects of anticancer agents on tumor growth correlated well with other methods for evaluating the effects of chemotherapy on BRO cells in vivo.
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PMID:[A simple method of testing the sensitivity to antineoplastic agents on human tumors in vivo]. 180 63

Activity of replicase complex enzymes involving thymidine kinase (TK), ribonucleotide reductase (RR), DNA-polymerases alpha and beta as well as DNA synthesis and single breaks in DNA were studied during growth of P388 ascites tumor. Under these conditions the rate of DNA synthesis was distinctly decreased via salvage pathway and de novo. Single breaks were not detected in the preexistent DNA within various periods after transplantation of P338 leukemic cells. Retardation of DNA synthesis during tumor growth correlated with a decrease in TK, RR and DNA-polymerase alpha activities, while DNA-polymerase beta activity was markedly increased. Growth of melanoma B16 was accompanied by a decrease in content of ATP, ADP, NAD, phosphocreatine and phosphosaccharides as well as by an increase in the level of inorganic phosphates.
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PMID:[Changes in the replication apparatus and phosphorus-containing metabolite pool in experimental tumors in animals during development]. 181 11

We studied the correlation between the formation of brain metastasis and the malignant growth potential of seven human melanoma cell lines, isolated from lymph node metastases (A375-SM, TXM-1, DM-4) or from brain metastases (TXM-13, TXM-18, TXM-34, TXM-40), and the potential of three variants of the mouse K-1735 melanoma. Growth rates in different concentrations of fetal bovine serum and colony-forming efficiency in semisolid agarose were measured, and the tumorigenicity and metastatic ability were determined in nude mice (for the human melanoma cell lines) or in C3H/HeN mice (for the K-1735 variants). The ability to form brain metastasis was tested by injection of cells into the carotid artery. A high colony-forming efficiency in agarose, especially at concentrations of agarose greater than 0.6%, corresponded with high tumor take rates, rapid tumor growth rates, and metastatic colonization of the lungs of the recipient mice. For the human melanomas, the lymph node metastasis-derived cells were more tumorigenic and metastatic than the brain metastasis-derived cells. In the K-1735 mouse melanoma, the tumorigenic and metastatic behavior of the cells after i.v. and s.c. injection corresponded with growth in agarose cultures. However, for growth in the brain after intracarotid injection, the different melanoma cell lines showed similar frequencies of tumor take, regardless of tumorigenicity in other sites of the recipient mice, although mice given injections of brain metastasis-derived cells survived longer than mice given injections of lymph node metastasis (human melanoma) or lung metastasis (K-1735 M-2)-derived cell lines. The results from the human and mouse melanoma cell lines show that the brain metastasis-derived cell lines were not more malignant than the lymph node or lung metastasis-derived cells. These data imply that the production of brain metastasis is not always the final stage of a metastatic cascade.
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PMID:Malignant potential of cells isolated from lymph node or brain metastases of melanoma patients and implications for prognosis. 182 30

There has been a long-standing clinical impression that tumor grow more slowly in elderly patients, but, because of confounding variables, this impression has been difficult to substantiate by epidemiologic data. Animal models offer a way to explore the relationship between host age and tumor growth under more controlled conditions. Our studies with murine B16 melanoma xenografts, discussed here, show that tumor growth and spread is in fact reduced in older animals and suggest that age-associated changes in immune function may be partially responsible.
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PMID:The influence of immunosenescence on tumor growth and spread: lessons from animal models. 182 41

We evaluated the predictability to clinical response of experimental effects of various anticancer agents on human cancer--nude mouse panel established in our department. The human cancer lines used were 12 gastric, 4 colorectal, 3 breast, 2 pancreatic cancers and 1 melanoma xenografted into BALB/c athymic nude mice under SPF conditions. Seven mice each with equivalent mean volume of sc inoculated tumor (about 100 mm3) were subjected to the treatment and control groups. Experimental treatment was conducted daily 25 times for antimetabolites, and intermittently 5 times once or twice a week for other drugs. Dosage of each drug adopted was maximal tolerated dose predetermined for the treatment schedule. Four weeks after the initiation of treatment, the therapeutic effect of each experiment was evaluated by the tumor growth inhibition rate (IR) based on the comparison of mean tumor weight between the 2 groups. When the IR was greater than 58%, the drug was evaluated as effective. The clinical response rate of each drug was referred from the result of the phase II study. Direct comparison of effects on 16 experimental chemotherapies in xenografts with responses to the corresponding clinical therapy of each donor patient revealed a fairly high accordance rate (94%). To elucidate the value of human cancer--nude mouse panel as the preclinical secondary screening, the response rates of 8 anticancer drugs treated to 15 cancer xenografts were compared with the cumulative clinical data available in each drug. Generally, the response rates of the human cancer xenografts to the drugs showed fairly good correlations with the cumulative clinical response rates of the corresponding drugs to the same organs. Using this panel, preclinical examinations of 6 new agents under development, including 254 S and other 2 CDDP derivatives, were performed in expectation the positive correlation with further clinical data.
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PMID:[Predictability of preclinical evaluation of anticancer drugs by human gastrointestinal cancer--nude mouse panel]. 185 13

We treated 60 invasive primary human melanomas by soft X-rays. In 23 additional cases radiotherapy was applied after total excision of a primary melanoma. Only in two cases was a tumor observed in the field of irradiation during the follow-up period: a recurrence of a primary melanoma and a skin metastasis. Radioresistance cannot be unequivocally assumed in either case. Since deeply situated in-transit metastases cannot be destroyed by soft X-rays in spite of our good results we regard radiotherapy of invasive primary melanomas as a second choice treatment to be administered if impaired general health, excessive tumor growth in certain localisations or refusal of the patient do not allow a major operation. Nodular parts of primary melanomas should be excised before radiotherapy to obtain material for histopathological confirmation of the diagnosis and to determine the thickness of the tumor. X-rays of lower hardness can subsequently be applied.
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PMID:Radiotherapy of primary human melanomas--experiences and suggestions. 185 13

Understanding tumor growth patterns has implications for prognosis as well as for response and susceptibility to treatment. The antibody Ki-67 was used as a marker of cycling cells and bromodeoxyuridine (BrdUrd) was used as a marker of proliferating cells to characterize the cycling and proliferative rates of cells from human choroidal melanoma. The BrdUrd labeling indices varied from 0-1.1% and the Ki-67 labeling indices ranged from 0-3.0.3%. Linear regression modeling showed good correlation defined by the equation: Ki-67 index = 0.237 + 1.63 x BrdUrd labeling index with r = 0.919. Correlations between these indices and clinical and histologic parameters were not significant.
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PMID:Ki-67 and bromodeoxyuridine labeling of human choroidal melanoma cells. 188 33


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