EVALUATION OF THE DIAGNOSTIC ROLE OF P63 IMMUNOSTAINING IN ASPIRATION CYTOLOGY BY SMEAR OR CELL BLOCK PREPARATION FOR THE CHARACTERISATION OF BREAST LESIONS

A study was conducted to determine the diagnostic role of p63 in breast FNAC sample for proper identification of myoepithelial cells. The sample comprised of 51 patients with breast lesions who have undergone FNAC and subsequently biopsy. Following conventional smear preparations, the entire materials fixed and processed for histopathology staining. The cell blocks were embedded in paraffin, sectioned and processed for Immunostaining. As p63 is a reliable nuclear marker of myoepithelial cells in the breast, it was used to distinguish these cells from their mimics in FNABs. Benign lesions usually contained p63 positive myoepithelial cells, and it was demonstrated that it may be a useful marker for highlighting these cells. p63 positive cells were also observed frequently in samples of DCIS and IDC, although, based on careful cytomorphologic evaluation, they may have been classified correctly as malignant cells. Hence, based on previously published data and on our findings, we advocate that anti-p63 antibodies may be used to identify myoepithelial cells as well as to overcome the cytomorphologic distortion of myoepithelial cells in FNABs of the breast.