Comparison of benign keratoses using p53, bcl-1, and bcl-2.

While cell-cycle markers have been used to differentiate benign vs. malignant lesions and to classify malignant lesions, benign keratoses have not been well studied using such markers. We hypothesized that inflammation or irritation of benign keratoses may be related to a shift in the cell cycle. We compared the immunohistochemical staining patterns of 10 seborrheic keratoses (SKs), 10 inflamed seborrheic keratoses (iSKs), and 10 inverted follicular keratoses (IFKs) using antibodies to p53, bcl-1, and bcl-2. Staining with antibodies to p53 was slightly increased in IFKs compared with iSKs or non-inflamed seborrheic keratoses. Bcl-1 staining was similar in all lesions. A population of bcl-2-positive dendritic cells was seen within the epidermal portion of IFKs. Keratinocyte bcl-2 staining was significantly higher in SKs compared with the other two keratoses. Bcl-2 may be increased in SKs as an anti-apoptotic mechanism.