Immunohistochemical expression analysis of BLCAP in FFPE breast tissue samples.

Abstract

<p>(A) No immunostaining was observed in a normal breast tissue section reacted with BLCAP antibody preincubated with immunizing peptide. (B) Immunohistochemical staining of BLCAP protein in a normal breast tissue sample demonstrated the presence of the BLCAP antigen in luminal epithelial cells with weak cytoplasmic expression (black arrow). Marked nuclear expression was also observed occasionally (red arrow). Yellow arrow points to a vessel with moderate immunoreactivity for BLCAP. (C) In a few cases IHC analysis of tumor samples showed that BLCAP was expressed in tumor cells with weak cytoplasmic expression (red arrow). (D) Most cases showed moderate to strong cytoplasmic expression with no detectable nuclear presence (red arrow) but in some cases (E) we could observe strong nuclear expression of BLCAP (red arrow). (F) In a few cases, samples were heterogenous with some cells showing distinct perinuclear immunoreactivity for BLCAP (red arrow). (G) Malignant cells showed stronger immunoreactivity (red arrows) than adjacent normal-looking ducts (black arrow), demonstrating up-regulation of this protein in tumor cells. Yellow arrows point to vessels with strong immunoreactivity for BLCAP. (H) We also observed up-regulation of BLCAP in early lesions where lobular carcinoma in situ cells showed overexpression of this protein (grey arrows) in relation to normal adjacent areas (black arrow), and at levels comparable to invasive carcinoma cells (red arrow).</p