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Three distinct subpopulations of tumor cells derived from a single parent strain BALB/cfC3H mammary adenocarcinoma were tested in vivo for sensitivity to cyclophosphamide, methotrexate, and 5-fluorouracil. Treatment was begun either 2 days after s.c. tumor cell injection or at the time when the tumors became palpable. It was given on a weekly basis for 4(More)
Ductal carcinoma in situ (DCIS) is becoming increasingly common, accounting for 25%–30% of newly diagnosed cases of breast cancer (1). The comedo type represents about 40% of the cases and carries the worst prognosis (2). The subsequent incidence of recurrence in patients presenting previously with comedo DCIS was 20% compared with 5% for noncomedo DCIS in(More)
A series of mouse mammary tumor subpopulation lines were compared for growth properties and sensitivity to chemotherapeutic drugs when grown as boluses in a collagen gel matrix versus in monolayer culture. Although the cell lines exhibited characteristic rates of bolus expansion in collagen, this growth was not paralleled by an exponential increase in cell(More)
The hypothesis that individual tumor subpopulations which differ in sensitivity to chemotherapeutic agents can influence each other's drug sensitivity was investigated using a set of mouse mammary tumor subpopulations derived from the same tumor. In one set of experiments, syngeneic mice were given injections of cyclophosphamide (CY)-sensitive line 168(More)
Four transplantable tumors, three (66, 410, and 168cl) isolated from a spontaneously occurring strain BALB/cfC3H mammary tumor and one (D2) arising from a BALB/c hyperplastic alveolar nodule were found to grow better in mammary fatpads than at s.c. sites. Furthermore, tumor growth was better (p less than 0.05) in intact mammary glands than in cleared(More)
A sequential, quantitative loss of Peanut agglutinin (PNA) binding with progression of mouse mammary cells from normal to preneoplastic to neoplastic phenotypes was observed. Normal mammary epithelium, preneoplastic mammary lesions designated D2HAN (D2-type hyperplastic alveolar nodules) and a series of nine spontaneous tumours (D2ST1, D2ST2, D2ST3, D2ST4,(More)
Mouse mammary tumors grow preferentially upon transplantation into intact mammary glands compared to cleared mammary fat-pads. Both sites provide stroma of the orthotopic site, but the latter lacks epithelial elements. If epithelium from enzymatically dissociated normal mammary glands is added to the tumor cells prior to injection into cleared fat-pads,(More)
In order to quantitate the effects of tumour subpopulation interactions, we have devised a method to determine the subpopulation composition of tumours by using paired tumour cell lines able to grow in different selective media. Line 4T07 forms colonies in thioguanine but not in HAT and line 168 forms colonies in HAT but not in thioguanine. An independent(More)
In order to examine in detail the sensitivity to chemotherapy of tumour cells at various organ sites and at various stages of metastasis, we have used a series of cell lines, all selected from sister subpopulations derived from a single mouse mammary tumour, which can be distinguished and quantitated from normal cells and from each other through growth in(More)
When mixtures of cell lines 168 and 4T07, both derived from the same mouse mammary tumor, were injected into syngeneic mice, the resulting tumors, analyzed over a large size range by colony-forming assays in selective media, consisted primarily of line 4T07, even when the ratio injected was 100:1 or greater in favor of line 168. This result indicated a(More)