Abstract
Purpose :
Sebaceous cell carcinoma (SCC) is the second most common eyelid malignancy. In order to grow and metastasize, aggressive cancers modify their lipid metabolism. Sterol regulatory element binding protein one (SREBP-1) is a transcription factor that acts as a main regulator in lipid synthesis. SREBP-1 overexpression is correlated with aggressive tumors, including breast, prostate and liver carcinomas. The aim of this study is to analyze the histopathological expression of SREBP-1 in SCC compared to normal sebaceous glands.
Methods :
In total, 19 SCC were evaluated. Normal sebaceous glands within the same SCC were used as internal positive controls. Immunohistochemistry using the Ventana Benchmark Automated Platform was performed on paraffin-embedded samples using a monoclonal anti-SREBP-1 antibody. Slides were digitized using the Aperio Scanscope Scanner. Expression was evaluated using the German Immunoreactive Score as follows: intense cytoplasm staining in malignant cells (2+); mild staining in the cytoplasm of malignant cells (1+), no staining in the cytoplasm of malignant cells (0), and further subclassified by the extent of staining as localized (1+) or diffuse (+2). Statistical analysis was performed using Fischer’s Exact Test; P<0.05 was considered significant.
Results :
SREBP-1 expression was positive in all 19 SCC, in both the Pagetoid spread within the epidermis as well as in the areas of dermal invasion. In 17 SCCs (89%), the score was 2-4, while a score of 0-1 was obtained in 2 SCC (11%). All normal sebaceous glands were positive for SREBP-1. In 4 samples (21%), the score was 2-4, whereas 14 normal sebaceous glands (79%) were scored 0-1. We also observed that in SCC the expression of SREBP-1 was predominantly diffuse (89%) compared to normal sebaceous glands which was localized (84%; P=0.0001). SREBP-1 expression in SCC was statistically higher compared to normal sebaceous glands (P=0.0002).
Conclusions :
To the best of our knowledge, this is the first study to analyze the expression of SREBP-1 in SCC. The results showed that SREBP-1 is an excellent marker for SCC. The higher score of SREBP-1 in SCC compared to normal sebaceous glands suggests that this marker correlates with malignant transformation in this tumor type.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.