The diagnostic and prognostic importance of cytogenetic aberrations identified in spontaneously occurring canine malignant lymphoma
Abstract
The hypothesis of this investigation was that specific, nonrandom chromosomal aberrations occur, are identifiable karyotypically, and are of prognostic significance in dogs with spontaneously occurring malignant lymphoma. A previous retrospective study of 105 dogs with spontaneously occurring malignant lymphoma demonstrated that sex, age, weight, World Health Organization (WHO) clinical stage, pre-treatment performance status, histopathological subtype and grade, treatment protocol, and response to treatment were of no prognostic significance for first remission length or survival time (all p $>$ 0.05). Chromosomal aberrations have been reported previously in the lymphocytes of dogs with malignant lymphoma, however, an insufficient number of cases have been observed to determine the diagnostic and/or prognostic significance of these and other reported aberrations. In this investigation, 84 dogs were presented prospectively to the Purdue University Veterinary Teaching Hospital and were routinely clinically staged and histopathologically graded. A lymph node biopsy was also obtained in all dogs for short-term tissue culture and subsequent cytogenetic evaluation. Sixty-one of the 84 dogs were completely evaluable for determining the prognostic significance of clinical stage, histopathological grade, and chromosomal aberration. The results from life table analysis demonstrated that first remission length and survival time were significantly longer in dogs having a trisomy of chromosome 13 as the primary chromosomal aberration than dogs with other primary chromosomal aberrations (e.g., monosomy of chromosome 15; (p $<$ 0.05)). Furthermore, dogs which received greater than five treatment cycles of an anthracycline chemotherapy, or were in complete remission at either three weeks or six weeks after treatment initiation had a significantly longer duration of first remission length and survival time than did other dogs (p $<$ 0.05). Sex, age, weight, histopathologic subtype and grade, WHO clinical stage, WHO and modified Karnofsky performance status, chromosomal modal number, and treatment protocol were of no prognostic importance in predicting first remission length or survival time (p $>$ 0.05). Multivariate analysis did not identify a significant correlation between the prognostic groups or within the various prognostic subsets (p $>$ 0.05).
Degree
Ph.D.
Advisors
Richardson, Purdue University.
Subject Area
Veterinary services|Genetics|Oncology
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