High-grade PIN : Keratin 34bE12
Benign prostatic glands have an intact basal cell layer. Adenocarcinoma is devoid of basal cells. In high-grade PIN (shown here), the basal cell layer is present but discontinuous. The image shows immunostaining with basal cell specific marker - high molecular weight cytokeratin. Note the triangular profiles of the basal cells as they rest on the basement membrane wedged between adjacent acinar cells.