BALB/c mice were immunized with a human melanoma cell line, SK-MEL 28, and their spleen cells were fused with mouse NS-1 myeloma cells. Hybrid cells were tested in an indirect 25SI-labeled protein A assay for production of antibodies that bound to surface antigens of SK-MEL 28 melanoma cells but not to autologous skin fibroblasts. One hybridoma, designated 4.1, had the required specificity. It Many human neoplasms express tumor-associated antigens (1). With few exceptions, however, methodological difficulties have hampered attempts to purify and to characterize these antigens. Monoclonal antibodies produced by hybridomas (2) offer great promise as a means of identifying tumor-associated antigens (3). The antibodies can also be used to purify the antigens by immunoprecipitation for subsequent biochemical characterization.Antigens associated with human melanomas have been studied extensively. Melanoma patients have been found to mount both cell-mediated and humoral immune reactions to their tumors (4, 5), and serological studies with melanoma patients' sera indicated the presence of two classes of melanoma-associated antigens (6). Antigens of one class are each restricted to a single melanoma. Those of the other class are shared by many melanomas and a small fraction of other tumors.Yeh and coworkers (7) The various target cell lines were grown in 5% CO2 in air in Waymouth's culture medium buffered with NaHCO3 and supplemented with 30% fetal calf serum, 1% nonessential amino acids, 1 mM sodium pyruvate, and 2 mM L-glutamine (7).

Mouse NS-1 myeloma cells were fused with spleen cells from mice that had been immunized with cells from a human melanoma, M1804. Hybrid cells were grown in selective medium and tested for production of antibody to surface antigens of M1804 cells. Three hybrids that produced antibodies that bound to the melanoma cells but not to autologous skin fibroblasts were cloned. Antibodies produced by two of the clones were cytotoxic to M1804 cells in the presence of rabbit complement. Extensive specificity tests showed that the antibodies produced by the clones bound strongly only to M1804 cells; significant, although weaker, binding occurred with 2 of 11 allogeneic melanomas. Apart from weak binding of the antibody produced by one of the clones to a breast carcinoma, binding assays of five carcinomas, one sarcoma, and fibroblasts from 17 individuals were negative, as were cytotoxic tests of 10 lymphoblastoid cell lines and peripheral blood lymphocytes from 68 normal donors and 12 chronic lymphocytic leukemia patients. This suggests that we have identified one or more determinants of a melanoma-associated antigen(s), whose expression is limited to a small proportion of melanomas. Human melanomas express cell surface antigens to which melanoma patients can mount an immune response (1). Sera from such patients sometimes contain antibodies to cell surface antigens of their melanomas. In some cases the antigens have been detected only on the patient's own melanoma (2, 3), and in other cases, also on allogeneic melanomas (3-5). There is also evidence for cell-mediated immunity, both to antigens whose expression is limited to a small number of melanomas (6) and to antigens that are shared by most, or possibly all, melanomas (7-9).The introduction by Kohler and Milstein (10) (see also ref. 11) of a method for producing large amounts of monoclonal antibodies of defined specificity promises to revolutionize serological analysis of tumor antigens. Koprowski et al. (12) have used this approach and obtained a monoclonal mouse antibody that identifies what may be a melanoma-specific antigen.This paper reports the results of a fusion of mouse NS-1 myeloma cells with spleen cells from mice that had been immunized with a short-term explant of a human melanoma (M1804). Three of the cell hybrids produced antibodies that bound to the immunizing melanoma, but not to autologous skin fibroblasts. These hybrids have been cloned and tested extensively by means of a '2-I-labeled protein A (12'I-protein A) binding assay and complement-dependent cytotoxicity assays. Results have shown that the antibodies produced by the clones define antigenic determinants expressed strongly on M1804 melanoma cells and weakly on some allogeneic melanomas, but not appreciably on other human cell types. MATERIALS AND METHODSCells. M1804 is a short-term explant of a melanoma metastasis that was removed from a lymph node of a 51-yr old white male 6 months after excision of the primary tumor (superficial spreading L III). Skin fibroblasts from the same patient...

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Berberine (BBR) is a natural alkaloid with significant antitumor activities against many types of cancer cells. This study investigated the molecular mechanisms by which BBR suppresses the growth of HER2-overexpressing breast cancer cells. The results show that BBR induces G1-phase cell cycle arrest by interfering with the expression of cyclins D1 and E and that it induces cellular apoptosis through the induction of a mitochondria/caspase pathway. The data also indicate that BBR inhibits cellular growth and promotes apoptosis by down-regulating the HER2/PI3K/Akt signaling pathway. Furthermore, it is also shown that a combination of taxol and BBR significantly slows the growth rate of HER2-overexpressing breast cancer cells. In conclusion, this study suggests that BBR could be a useful adjuvant therapeutic agent in the treatment of HER2-overexpressing breast cancer.

Several studies have investigated the associations between diet and endometrial cancer, but few have focused specifically on coffee and tea. In a hospital-based case-control study, we examined the associations between endometrial cancer risk and usual consumption of coffee, decaffeinated coffee, and black tea among 541 women with endometrial cancer and 541 women with an intact uterus but without a cancer diagnosis seen at Roswell Park Cancer Institute (Buffalo, New York) between 1982 and 1998. Daily frequency of consumption of coffee, decaffeinated coffee, and black tea in the few years prior to diagnosis in cases and questionnaire completion in controls was assessed with a self-administered epidemiologic questionnaire and categorized as none, 0.5 cups/d, 1-2 cups/d and >2 cups/d. Odds ratios (OR) and 95% confidence intervals (CI) for each category referent to nondrinkers were estimated with unconditional logistic regression adjusting for age, endometrial cancer risk factors and each beverage mutually adjusted for other beverages. Compared to nondrinkers, we observed a nonsignificant negative association with endometrial cancer risk among women who reported >2 cups/d regular coffee (OR 0.71, 95% CI 0.49-1.03), a significant inverse association with >2 cups/d black tea (OR 0.56, 95% CI 0.35-0.90) and a significant inverse association with >4 cups/d combined coffee and tea consumption (OR 0.47, 95% CI 0.28-0.80). These findings suggest coffee and tea may be important in reducing endometrial cancer risk.

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Thirty surgical samples of squamous cell carcinoma of the cervix obtained from Chinese women were analysed for the presence of human papillomavirus (HPV) types 16 and 18 using Southern blot hybridization procedure. HPV16 was detected in 53% while HPV18 was found in only 6% of the samples analyzed. When compared with other reports, variation in the geographic distribution of these two HPV types in association with cervical carcinoma is noted. Thirty-seven and a half percent of the HPV16-positive samples contained this HPV type in episomal form and an equal number in cellular DNA-integrated form. The simultaneous presence of both episomal and integrated forms was found in the remaining 25% of the positive samples. The two HPV18-positive cases harbored only episomal viral genome and were not superinfected by HPV16. Analysis of the HPV16 integration samples showed that single integration events had probably occurred and some of the viral sequences had been lost on or subsequent to integration.

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