Histone 1.5: A Novel Prostatic Cancer Marker Superior to AMACR: An Immunohistochemical Study
Vadim Khachaturov, Guang-Qian Xiao, Yayoi Kinoshita, Pamela D Unger, David E Burstein. Mount Sinai School of Medicine, New York, NY
Background: Histone H1.5 (HH1.5) is part of the linker histone families, which is located in the nucleus and plays a role in chromatin structure and gene expression. HH1.5 is expressed more in pluripotent cells than in differentiated cells and may contribute in self-renewal mechanisms. AMACR is frequently used to distinguish benign from malignant prostatic lesions with approximately 25% false positive and false negative results. The aim of this study was to investigate the diagnostic and prognostic role of HH1.5 in prostatic cancer.
Design: Sixty-nine routinely formalin fixed and paraffin embedded prostatic needle biopsies were immunohistochemically stained for HH1.5 (1:800), of which 67 cases had prostatic cancer, ranging from Gleason 3 to 5. High grade prostatic intraepithelial neoplasia (HPIN) was also evaluated when present in the specimen. Nuclear staining of HH1.5 was considered positive.
Results: The majority of prostatic cancer cases (91%) showed strong reactivity for HH1.5. In contrast, only 10% of benign prostatic glands showed focal weak positivity. HPIN also stained focally and weakly for HH1.5. In addition, increased HH1.5 staining was observed in high grade prostatic cancer versus lower grade (74% vs 59%). Background lymphocytes when present were uniformly and strongly reactive with HH1.5. The results are summarized in Tables 1 and 2.
|HH1.5||61∗ (91%)||7† (10%)||23‡ (100%)|
|Intensity||Gleason 3||Gleason 4/5||Metastatic|
|Neg.||4 (7%)||6 (14%)||1|
|1+||19 (34%)||5 (12%)||0|
|2+||33 (59%)||32 (74%)||4 (80%)|