title: Experimental model for locally recurring mammary tumors. Development, morphology, karyotype, growth kinetics, and experimental metastatic potential.
abstract: A rat model was established for evaluating the biology of locally recurring mammary tumors after surgical resection of the primary tumor. Eight distinct cell lines were independently derived from primary tumors and local recurrences after surgical removal of 13762NF rat mammary adenocarcinoma clone MTF7(T20). In vivo tumor doubling times between the "parental" MTF7(T20) cell line, primary tumor-derived cell lines sc1 and sc3, and the local recurrence (LR) sublines varied after the inoculation of 10(6) tumor cells into the mammary fat pad of female Fischer 344 rats. Doubling times were shorter for LR3, and LR4, LR5, and LR6 than their primaries sc3 and MTF7(T20), respectively, and longer for LR1 and LR1a than their primary tumor sc1. The LR sublines varied considerably for their experimental metastatic potentials. Both increases and decreases in metastatic potential were seen compared to MTF7(T20), sc1, and sc3. Karyotype analysis by G-banding revealed the presence in the LR sublines of several marker chromosomes, previously identified in MTF7 at tissue cultures 11 and 35. Two new chromosome markers were identified: M54, shared by MTF7(T20), sc1, LR4, LR5 and LR6, and M55, shared by MTF7(T20), sc1, LR1, sc3, LR3, LR4, and LR6. These data indicate that local tumor regrowth after surgical excision of the primary tumor in this model most likely selects the growth of tumor cell subpopulations already present within the primary tumor. Differences in growth kinetics, karyotype, and metastatic potential between the parental MTF7(T20), primary tumors sc1 and sc3, and their LR sublines may reflect in vivo influences on the phenotypic diversity generated during the development of local mammary tumor recurrences after surgical treatment of the primary tumor.
authors.affiliation: Department of Pediatrics, H. Lee Moffitt Cancer Center and Research Institute, University of South Florida College of Medicine, Tampa 33682-0179.
authors.forename: J
authors.initials: J
authors.lastname: Estrada
authors.forename: D L
authors.initials: DL
authors.lastname: Freeman
authors.forename: P A
authors.initials: PA
authors.lastname: Aeed
authors.forename: D R
authors.initials: DR
authors.lastname: Welch
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery / Q000648:ultrastructure; D000818:Animals; D002453:Cell Cycle; D002460:Cell Line; D004195:Disease Models, Animal; D005260:Female; D007621:Karyotyping; D008175:Lung Neoplasms / Q000556:secondary / Q000648:ultrastructure; D008325:Mammary Neoplasms, Experimental / Q000473:pathology* / Q000601:surgery / Q000648:ultrastructure; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000601:surgery / Q000648:ultrastructure; D051381:Rats