Mammary tumors in dogs and cats
Based on the molecular
profile, a new classification for canine
mammary carcinoma has been developed and it is assigned into:
hormone receptor positive (luminal A and B) and hormone receptor
negative (ERB-B2, basal-like, normal-like). In Human Medicine this
classification is used to estimate the correlation
between the primary tumor and its related metastasis. In order to
provide, also in Veterinary Medicine the availability of the latter
data, that has predictive value on the estimation of the
effectiveness of target therapies, it is of rilevant
importance to determine whether the molecular phenotype of
the lymph node and / or systemic metastases is the
same of the primary neoplasm. Cases of feline and
canine mammary carcinoma will be selected and classified
according to the molecular profile and the obtained phenotypes will
be compared with the respective lymph node and/or systemic
metastases phenotype.
Vasculogenic mimicry in tumors of dog and cat
Recently, it has been shown, in canine inflammatory mammary
carcinomas, the existence of the so called "vasculogenic mimicry
phenomenon", which is the capacity of the neoplastic
cells to form canaliculi or vessels-like structures that are able
to transport blood and cells . The presence of this phenomenon in
tumors makes them obviously more aggressive, with
greater possibility to growth and metastatize compared to
other neoplasms that do not exhibit the same phenomenon, and
it also makes them unfit to be treated with angiogenesis
inhibiting drugs.
Canine and feline mammary tumors
The characterization of the molecular profile
of canine and feline mammary tumors is the key to
the development of prognostic-predictive models and therapeutic
targeted options. This study aimed to estimate the relation between
the molecular phenotype primary tumor and its related lymph-node
metastasis.120 cases of mammary tumors were collected,
60 cases of dogs and 60 of cats, including for
each case both the primary tumor and the respective node
metastasis. The samples were collected from both the
Service of Pathological Anatomy, Department of Veterinary Medical
Sciences of Bologna and by the Department of Pathology, Department
of Animal Pathology Prophylaxis of Food Hygiene of the University
of Pisa. Immunohistochemistry staining was performed with a panel
of antibodies against -ER, -PR, - ERBB2, 5-6-CK, CK-14, CK-19-P63.
The algorithm used for the formulation of the taxonomy was
based on the modified algorithm by Sassi et al. The first results,
obtained on a few number of cases, showed both in dogs and
cats the phenomena of concordance (same molecular profile between
primary tumor and lymph node metastasis) that discordance
(different molecular profile between primary tumor and lymph node
metastasis). The latter results are in accordande with
the two main theories about the metastatic power: discordance
phenotypes are index of a late selection of cancer cells in the
carcinogenesis process, while concordance is explained by an
intrinsic and early metastatic ability of the dominant phenotype in
the primary tumor. The predictive-therapeutic value based on the
phenotype of the primary tumor can be functional only in
concordant cases.
Vasculogenic mimicry in canine and feline tumors
From the database of the Department of Pathology,
Department of Veterinary Medical Sciences of Bologna cases of
melanoma, gastrointestinal carcinoma, bladder and prostatewill be
selected in order to verify the existence of the phenomenon of the
vasculogenic mimicry. Cases will be stained
with hematoxylin-eosin and in those, with aspects that can be
related to the vasculogenic mimicry, will be stained with PAS
staining to demonstrate the deposition of a tubular pattern in
the extracellular matrix. The immunohistochemical technique will be
performed with different antibodies such as anti-CD31
antibody to demonstrate that the examined vessels are not covered
by true endothelial cells. A further demonstration will be carried
out using anti-cytokeratin antibodies (in the case of carcinomas)
to highlight the neoplastic epithelial cells that surround vessels.
Melan A will be used to mark melanocytic cells. Only cases with PAS
positive matrix, negative vessels to CD31 but
positive to cytokeratin or to Melan A will be considered
as presenting the phenomenon of vasculogenic
mimicry.
