Progression of canine mammary tumours as reflected by DNA ploidy in primary tumours and their metastases.
Thirty dogs with metastasizing mammary tumours (carcinomas, n = 22; sarcomas, n = 8) were necropsied. Flow cytometric DNA analysis was carried out on frozen primary tumours and on selected metastases from the dogs. Ductular carcinomas (n = 13) had a varying growth pattern, in terms of histology, in both the primary tumours and metastases and between different metastases. The different types of DNA ploidy, including hypodiploidy, in the primary ductular carcinomas were also seen in the tumour metastases. Dogs with primary anaplastic carcinomas (n = 7) had multiple metastases, which were in most cases near-diploid or hyperdiploid. Two dogs had spindle-cell carcinomas, which were hypodiploid in both the primary tumour and the metastases. The DNA ploidy in the metastases was retained in 16 of the 22 dogs with primary carcinomas. Fibrosarcomas (n = 5) showed different types of DNA ploidy. In two of the three dogs with diploid or near-diploid osteosarcomas, the DNA ploidy was retained in the metastases. There was a statistically significant association between mammary tumours and metastases (P = 0.0001) in terms of both histological diagnosis and DNA ploidy. The association was retained when the carcinomas were tested separately (P = 0.0001); in the sarcomas it was retained weakly in terms of histology (P = 0.0183) but not DNA ploidy (P = 0.6659). The retention of the DNA ploidy in most carcinoma metastases indicated that selection of DNA ploidy had taken place prior to metastasis. The differences in patterns of DNA ploidy between ductular and anaplastic carcinomas may reflect different pathogenesis in these types of canine mammary tumour.
Hellmén
E
E
Department of Pathology, Swedish University of Agricultural Sciences, Faculty of Veterinary Medicine, Uppsala, Sweden.
Svensson
S
S
D000818:Animals; D002277:Carcinoma / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000235:genetics / Q000473:pathology / Q000556:secondary; D004273:DNA, Neoplasm / Q000032:analysis*; D004285:Dogs; D005260:Female; D005354:Fibrosarcoma / Q000737:chemistry / Q000235:genetics* / Q000473:pathology / Q000556:secondary; D015674:Mammary Neoplasms, Animal / Q000235:genetics* / Q000473:pathology; D012516:Osteosarcoma / Q000737:chemistry / Q000235:genetics* / Q000473:pathology / Q000556:secondary; D011003:Ploidies
D004273:DNA, Neoplasm