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Background: Progression of proliferative breast disease has been associated with increased risk for development of invasive carcinoma. Cell lines have been developed to facilitate the study of this process. Human cell line MCF10A originated from spontaneous immortalization of breast epithelial cells obtained from a patient with fibrocystic disease, and cell lines MCF10AneoN and MCF10AneoT were created by stable transfection of these cells with the neomycin-resistance gene and either the HRAS gene or the mutated T-24 HRAS gene, respectively. Purpose: Our goal was to develop an experimental model of progressive human proliferative breast disease. Methods: MCF10A, MCF10AneoN, and MCF10AneoT cells were injected subcutaneously into the dorsal flank of male nude/beige (C57/BALB/c nu/nu bg/ bg) mice (12 mice for each cell type). These mice were examined periodically for formation and persistence or growth of palpable nodules. One mouse per group was killed 1 week after cell injection; thereafter, mice were observed as long as possible. Cells were recovered from palpable lesions by enzymatic dissociation of the excised lesions. Cells re-established in tissue culture from a week-14 tumor MCF10AneoT.TG1) were injected into 12 male nude/beige mice. Southern blot hybridization analysis of the HRAS gene locus and cytogenetic analyses were performed. Results: Transplanted MCF10A and MCF10AneoN cells formed transient, small palpable nodules that regressed and disappeared during the 4th and 5th weeks. In 10 of the 12 mice, T-24 HRAS genetransfected MCF10A cells MCF10AneoT) formed small, flat nodules that persisted for at least 1 year. Three of these xenografts became carcinomas. One (removed 7 weeks after transplantation) was an undifferentiated carcinoma composed of polygonal cells with large, vesicular nuclei and numerous mitoses. The second (removed after 14 weeks) was an invasive squamous cell carcinoma. The third (removed after 56 weeks) was a moderately differentiated adenocarcinoma. Initially, xenografts of MCF10AneoT.TG1 cells showed intraductal proliferative changes; after 23 weeks, the lesions showed histologic features resembling those seen in atypical hyperplasia of the human breast, and later lesions showed characteristics of carcinoma in situ. The MCF10 lineage of cells of three MCF10AneoT.TG1 xenografts was confirmed by DNA fingerprinting and karyotype analysis. Conclusions: MCF10AneoT and MCF10AneoT.TG1 comprise a transplantable xenograft model that produces a broad spectrum of human proliferative breast disease. Implications: The reproducible establishment of representative stages in early breast cancer progression from the MCF10 model offers a new opportunity to analyze critical events of carcinogenesis and progression in breast cancer.

Background: Prostatic carcinoma is both the most common invasive cancer and the second most common cause of cancer deaths in men in the United States. Before 1991, attempts to propagate prostatic carcinoma from primary tumors for periods longer than 3 months were unsuccessful in vivo and in vitro with rare exceptions. In 1991, we reported establishment of slowly growing tumors for six of 10 human primary prostatic carcinomas approximately 2-6 months after transplantation. However, none of the tumors were larger than 5 mm or serially transplantable. Purpose: Our purpose in this study was to determine whether human primary prostatic carcinoma could be grown as serially transplantable xenografts. Methods: Cells from primary prostatic carcinomas obtained from transurethral prostatic resections or total prostatectomies in 20 patients were injected subcutaneously into male nude mice on the day of surgery. Sustained-release testosterone pellets were placed subcutaneously in the mice 2-24 days before transplantation of tumors and at intervals of 10-12 weeks. Serial transplantations in subsequent generations of mice were carried out by similar methods. Chromosome analysis was performed on six tumors. Results: Six of 20 primary prostatic carcinomas have grown sufficiently to permit serial transplantation into second mice; four have been documented histopathologically in the second mouse and serially transplanted into three or more successive mice. When a single primary tumor was injected into several mice by the same procedure, tumors failed to grow in some recipients but became serially transplantable in others. Growth of these tumors is slow and irregular, with frequent regressions. Short-term cultures of 10 tumors, eight of which were injected into mice in parallel, were initiated on the day of surgery; CWR31, which was successfully transplanted serially, exhibited only aberrant metaphases and showed clonal, chromosomal changes in culture. Including CWR31, three of the six tumors for which chromosomal analysis was successful contained clonal aberrations. Preliminary studies of SCID (severe combined immunodeficient) mice suggest that they are not superior to nude mice for establishment of serially transplantable prostatic carcinoma xenografts. Conclusions: A proportion of human primary prostatic carcinomas can be grown as xenografts. Four new serially transplantable xenografts (CWR21, CWR31, CWR91, and CWR22) are currently propagated in our laboratory, a resource that was not previously available. Implications: Our experience suggests that the most important factor in serial transplantation is the collaboration of urologists and pathologists in expediting placement of the tumor in cold saline, examination of the frozen section, and transplantation. [J Natl Cancer Inst 85:394-398, 1993]

Background. Identifying markers that have the potential to predict tumor behavior is important in breast cancer because of the variability in clinical disease progression. Genetic alterations in tumors may appear as changes in total DNA content, individual chromosomes, single genes, or gene expression. Alteration in DNA content is an imprecise but accessible measurement of the genome. Diploid tumors have been associated with a better clinical outcome, and increased ploidy correlates with other indicators of poor prognosis. Concurrent analysis of DNA content with markers of genetic expression is feasible (e.g., myc oncogene) and may increase its prognostic power. Chromosomal studies could provide a more precise tool for localizing genetic damage, but there is little cytogenetic information about primary breast cancers, no convincing evidence has emerged to target locations in the karyotype that appear specifically altered, and many primary and cultured breast cancers contain cells that appear chromosomally normal. Attempts to define molecular markers have used probes of different chromosomal sites, some chosen because of logical associations with hormonal activity, known oncogenes, or tumor-suppressor genes, and some by chance. Currently, to the authors' knowledge, none has shown uniform changes by mutation, loss, or overexpression in all breast cancers, although a remarkable number of loci are altered to some extent. These lesions must be associated with particular disease subsets or, retrospectively, with differential survival if they are to have prognostic value. Methods. The authors examined several loci (ERBB2, INT2, MUC1) for gene amplification or loss of heterozygosity by Southern blotting and for gene expression by immunohistochemistry in breast tumors from patient groups selected by survival. Results and Conclusions. A retrospective series showed gene amplification at the erbB2 locus in 22% of rapidly recurrent (RR) tumors and 13% of tumors from long-term tumor-free survivors (LTS), but the difference was not statistically significant (P = 0.18). The erbB2 product was displayed histochemically with equal frequency between those with RR tumors and LTS patients. Moreover, the correlation was poor between different analytic measures on the same tumors. This result was tested using a prospective study of erbB2 to correlate DNA analysis with western blot findings and frozen and fixed histochemical results. Another oncogene, int2, showed significant correlation between amplification and recurrence; 16% of RR tumors showing genetic amplification (P = 0.02). Loci on other chromosomes, 1 (muc1) and 17 (cmm86), also are being investigated in groups selected for differences in survival.

While flow cytometry is useful in screening human cancers for chromosome abnormalities, only karyotyping is the definitive test. Karyotyping requires the growth of living cells from a biopsy or blood sample. The test demands skill and patience, and is generally not suitable for mass screening. Nevertheless, the cases of two patients with dedifferentiated chondrosarcoma illustrate that the karyotype provides information that is not available by other techniques. Chondrosarcomas are the second most common form of bone cancer. They usually affect older patients and generally occur as slow-growing low-grade cartilaginous growths. However, about 10 percent of chondrosarcomas lose their differentiated state (dedifferentiation) and become poorly differentiated aggressive high-grade cancers with a poor prognosis. Fresh chondrosarcoma tissue was obtained from two patients at surgery. Flow cytometric analysis was performed on both specimens; one was found to have the normal diploid chromosome complement, while the other was found to have a pathological aneuploid complement. Karyotyping was performed on cells and revealed abnormalities within the cells of both specimens. While numerous abnormalities were observed in both specimens, the aneuploid specimen was cytogenetically more complex, as would be expected. However, one defect was common to the chondrosarcoma cells from both patients. This common feature consisted of breaks in the short arm of chromosome 1. These breaks revealed themselves as a deletion in one chromosome homolog and recombination in the other. In both patients, the deletion and recombination occurred at the same chromosome band, in the region of 1p36. This same region is lost in neuroblastoma (a malignant cancer that usually affects infants and children) and has been shown to be involved in myxoid chondrosarcoma. It is not yet known if the 1p36 break will prove to be a consistent finding in these tumors. However, the same break occurring in both patients cannot be attributed only to coincidence; investigation of the genes near the 1p36 point is likely to reveal interesting mechanisms of the malignant transformation of cells. (Consumer Summary produced by Reliance Medical Information, Inc.)