IJUP08 - Universidade do Porto

MUC1 overexpression is associated with distant metastases
development in canine mammary carcinomas
de Oliveira JT 1,2 , Pinho S 1,2 , Matos AJ 2 , Lopes C 2 , Barros R 1,3 , Hespanhol V 3 , Reis
C 1,3 and Gärtner F 1,2
1Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Rua
Dr Roberto Frias s/n, 4200-465 Porto, Portugal
2 Institute of Biomedical Sciences of Abel Salazar (ICBAS), University of Porto, Largo Prof. Abel
Salazar, 2, 4099-003 Porto, Portugal
3 Medical Faculty, University of Porto, Alameda Prof. Hernâni Monteiro 4200-319 Porto, Portugal
Canine mammary tumours affect mainly older bitches and comprise approximately 25-
50% of all their tumours, 40-50% being malignant [1,2]. MUC1 is overexpressed in human
breast cancer and contributes to carcinoma progression [3,4]. High MUC1 expression is
linked to a poorer prognosis [5]. MUC1 expression had never been described in canine
mammary tumours (CMT) before.
The aims of this work where: to characterize MUC1 expression in CMT and to evaluate its
relationship with clinicopathological features such as tumour histological type, mode of
growth, tumour grading, lymph node metastases and distant metastases.
Fifty paraffin tumour sections were examined for MUC1 immunostaining patterns.
Immunohistochemistry technique, using antibody C-20, determined MUC1 expression.
Associations between clinicopathological features and MUC1 expression were analysed.
All tumours showed MUC1 immunostaining. In normal adjacent mammary gland tissue,
MUC1 was detected in the apical cell membrane. In the carcinomas MUC1 was detected in
the cytoplasm (52.0%), circumferential membrane (2.0%), or a mixture of both patterns
(46.0%). The follow up period was of 2 years, during which 10 distant metastases were
confirmed. We observed that a total of 20.4% of tumours gave rise to distant metastases,
among these and most importantly 100% showed significantly high (≥50% positive cells)
MUC1 expression (p= 0.03).
In the bitch, high MUC1 expression was significantly associated to higher metastatic
development. Our findings indicate, for the first time in CMT, that MUC1 may be an
important prognostic marker in these tumours as it is in human breast cancer.
References:
[1] Sorenmo, K. (2003), Canine mammary gland tumors, Vet Clin Small Anim, 33, 573-596.
[2] Owen, L.N. (1979), A comparative study of canine and human breast cancer, Invest Cell
Pathol, 2, 257-275.
[3] Baldus, S.E., Engelmann, K., Hanisch, F.G. (2004) MUC1 and the MUCs: a family of human
mucins with impact in cancer biology, Crit Rev Clin Lab Sci, 41, 189-231.
[4] Croce, M.V., Isla-Larrain, M.T., Rua, C.E., Rabassa, M.E., Gendler, S.J. (2003), Patterns of
MUC1 tissue expression defined by an anti-MUC1 cytoplasmic tail monoclonal antibody in breast
cancer, J Histochem Cytochem, 51, 781-788.
[5] Rakha, E.A., Boyce, R.W., El-Rehim, D.A., Kurien, T., Green, A.R., Paish, E.C. et al. (2005),
Expression of mucins (MUC1, MUC2, MUC3, MUC4, MUC5AC and MUC6) and their prognostic
significance in human breast cancer, Mod Pathol, 18, 1295-1304.
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