Immunohistochemical characterization of neoplastic cells of breast origin

Maria De Las Mercedes Noriega,Alejandra Avagnina,Silvana Nieto,Hugo Krupitzki,Valeria Cecilia Denninghoff,Florencia Perazzo,Boris Elsner,Alejandro Garcia,Néstor Lago,Fernando Paesani

doi:10.1186/1746-1596-7-73

Abstract

BackgroundAfter skin cancer, breast cancer is the most common malignancy in women. Tumors of unknown origin account for 5-15% of malignant neoplasms, with 1.5% being breast cancer. An immunohistochemical panel with conventional and newer markers, such as mammaglobin, was selected for the detection of neoplastic cells of breast origin. The specific objectives are: 1) to determine the sensitivity and specificity of the panel, with a special emphasis on the inclusion of the mammaglobin marker, and 2) to compare immunohistochemistry performed on whole tissue sections and on Tissue Micro-Array.MethodsTwenty-nine metastatic breast tumors were included and assumed as tumors of unknown origin. Other 48 biopsies of diverse tissues were selected and assumed as negative controls. Tissue Micro-Array was performed. Immunohistochemistry for mammaglobin, gross cystic disease fluid protein-15, estrogen receptor, progesterone receptor and cytokeratin 7 was done.ResultsMammaglobin positive staining was observed in 10/29 cases, in 13/29 cases for gross cystic disease fluid protein-15, in 20/29 cases for estrogen receptor, in 9/29 cases for progesterone receptor, and in 25/29 cases for cytokeratin 7. Among the negative controls, mammaglobin was positive in 2/48, and gross cystic disease fluid protein-15 in 4/48.ConclusionsThe inclusion of MAG antibody in the immunohistochemical panel for the detection of tumors of unknown origin contributed to the detection of metastasis of breast cancer. The diagnostic strategy with the highest positive predictive value (88%) included hormone receptors and mammaglobin in serial manner.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1366310812718988

Highlights

After skin cancer, breast cancer is the most common malignancy in women
Tumors of unknown origin represent a heterogeneous group of tumors that first manifest as metastasis in a patient with unknown history of disease, where the assessment fails to identify the primary tumor site at diagnosis
Takeda et al found a sensitivity of 45% and 50% for GCDFP-15 and MAG, respectively, in pulmonary and pleural metastasis from breast cancer [12]

Summary

Introduction

Breast cancer is the most common malignancy in women. Tumors of unknown origin account for 5-15% of malignant neoplasms, with 1.5% being breast cancer. Fritzsche et al showed 73.3% and 72.1% cytoplasmic positivity for GCDFP-15 and MAG, respectively, in invasive breast cancer (primary tumor) [10]. None of them is specific for this type of neoplasm, and they all express uneven positivity in other malignancies Their sensitivity for breast cancer is variable, the need to use them as panels and correlate the results with the morphology of the tumor. MAG-A could be the marker of choice to identify a tumor of breast origin [14] According to these findings, this novel antibody may be included in an immunohistochemical panel. We hypothesize that the inclusion of the MAG antibody to the immunohistochemical panel already routinely used would increase the positive predictive value in the detection of breast tumors of unknown origin

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