Figure 1.

Expression of specific (synaptophysin & chromogranin A) and non-specific (CD56 & CD117) neuroendocrine markers in normal breast tissue. (a) Expression of synaptophysin in luminal cells of normal breast tissue. (b) Synaptophysin expression in probably apocrine differentiated luminal cells (inset: strongly synaptophysin positive basal cell, consistent with a true neuroendocrine cell; however, no chromogranin A expression was seen in this area). (c) CD56 expression in a subset of normal luminal cells. (d) CD117 expression in the majority of luminal cells in normal breast tissue.