Table of Contents
ISRN Dermatology
Volume 2014, Article ID 348417, 6 pages
http://dx.doi.org/10.1155/2014/348417
Research Article

p16 Expression Is Lost in Severely Atypical Cellular Blue Nevi and Melanoma Compared to Conventional, Mildly, and Moderately Atypical Cellular Blue Nevi

1Department of Dermatology, Southern California Kaiser Permanente, Los Angeles Medical Center (LAMC), Kaiser Permanente, 4867 W Sunset Boulevard, Los Angeles, CA 90027-5969, USA
2Department of Pathology, Southern California Kaiser Permanente, Los Angeles Medical Center (LAMC), Kaiser Permanente, 4867 W Sunset Boulevard, Los Angeles, CA 90027-5969, USA

Received 15 September 2013; Accepted 21 October 2013; Published 22 January 2014

Academic Editors: M. Clelia, M. Feinmesser, and P. Quatresooz

Copyright © 2014 Laura M. Chang and David S. Cassarino. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Significant decreases in p16 expression have been shown to occur in melanoma compared to Spitz tumors, and loss of p16 staining has been found to correlate with melanoma tumor progression. However, comparison of p16 between atypical cellular blue nevi (CBN) and melanoma has not been reported previously. Methods. p16 immunohistochemical staining was evaluated in 14 atypical CBN, 8 conventional and atypical melanocytic nevi, and 16 melanomas, including 4 malignant CBN. p16 staining intensity was graded on a scale of 0–3 and the percentage of melanocytes stained with p16 was determined. Results. p16 staining was significantly higher in all CBN as a group when compared to melanomas ( ) and malignant CBN ( ). Higher p16 expression was also seen in mildly ( ) and moderately atypical ( ), but not severely atypical, CBN compared to melanomas. Conclusions. p16 immunohistochemical expression is higher in mildly and moderately atypical CBN compared to severely atypical CBN and melanomas. In conjunction with additional markers and histology, p16 staining may be useful in confirming the benign nature of these tumors, but is not useful in distinguishing severely atypical CBN from malignant cases, consistent with the overlapping histologic features between these tumors.