Expression of CD79A and immunoglobulins in the epithelium of canine mammary gland tumors.

Immunoglobulins (Ig) are traditionally considered as an exclusive product of B cell lineage and as molecules that play a crucial role in the regulation of the immune system mechanisms. Noteworthy, in the last decades, has been highlighted that many physiological and pathological “non B” cells, including epithelial cells and neurons may also express immunoglobulins (i.e. IgA, IgG and IgM). Igs, and their receptor CD79a, have been found in human cancerous cells and their role in cancerogenesis, as well as the therapeutic usefulness, has been raising interest [1,2]. On the basis of similarities among the epidemiology, biological behaviors, histopathological presentation and risk factors between the human and dog, our aim was to evaluate the epithelial expression of immunoglobulins in mammary gland tumors of the female dog. By the mean of immunohistochemistry, epithelial expression for CD79a and IgG, IgA ed IgM on 43 cases of mammary lesions (10 hyperplasia, 10 simple carcinoma, 5 solid carcinoma, 8 micropapillary carcinoma and 10 cases of mixed carcinoma) was evaluated. At the same time, an evaluation of number and distribution of CD79a+ immune cells was performed. In the mammary gland the number of CD79a+ immune cells decreased in hyperplastic area; in the malignant lesions, above all in peritumoral stroma, a high increase in the number of CD79a+ immune cells was observed. Rare cells were detectable in the intratumoral stroma. Moreover, the positivity for the antibody CD79a was also detectable in the basal cells of the solid tumors and in glandular cells of simple and micropapillary carcinomas. Both in preneoplastic and neoplastic lesions even with differences in intensity and cell localization, epithelial cells showed a positivity to IgA and IgG while the positivity for IgM was weak or absent. On the basis of our preliminary results and literature data, we suggest that such as immune cells and molecules could be directly involved in the progression or regression of mammary gland tumors as underlined by recent scientific evidences [3,4,5,6]. The canine mammary gland tumor, already recognized as a model in comparative oncology, represents once again an important support for the advancement of the veterinary oncology. [1] Chen Z., Qiu X., Gu J. 2009. Immunoglobulin expression in non-lymphoid lineage and neoplastic cells. Am J Pathol 174,1139-1148. [2] Hu D., Zheng H., Liu H. 2008. Immunoglobulin expression and its biological significance in cancer cells. Cell Mol Immunol. 5, 319-324. [3] Welinder C., Baldetorp B., Blixt O. 2013. Primary breast cancer tumours contain high amounts of IgA1 immunoglobulin: an immunohistochemical analysis of a possible carrier of the tumourassociated Tn antigen. PLoS One 8: e61749. [4] Yang B, Ma C, Chen Z, Yi W, McNutt MA, Wang Y, Korteweg C, Gu J. 2013. Correlation of immunoglobulin G expression and histological subtype and stage in breast cancer. PLoS One 8: e58706. [5] Ma C, Wang Y, Zhang G, Chen Z, Qiu Y, Li J, Luo J, Huang B, Jiang C, Huang G, Wan X, Korteweg C, Gu J. 2013. Immunoglobulin G expression and its potential role in primary and metastatic breast cancers. Curr Mol Med. 13: 429-37. [6] Hu F., Zhang L., Zheng J. 2012. Spontaneous production of immunoglobulin M in human epithelial cancer cells. PLoS One 7:e51423.