Abstract
Purpose :
Uveal melanoma (UM) is the most common intraocular malignant tumor in adults. Despite advances in diagnosis and treatment, the overall survival rate has not changed.
CD109 is a gene that encodes pro-metastatic factors. CD109 interacts directly with type I transforming growth factor-beta (TGF-ß) receptor and negatively modulates TGF-ß signaling. CD109 is highly expressed in squamous cell carcinoma of the lung and skin, urothelial carcinoma, breast carcinoma, epithelial sarcoma, oral squamous cell carcinoma as well as in cutaneous malignant melanoma.
The purpose of this study is to evaluate CD109 expression and its role as a possible therapeutic target in UM.
Methods :
Thirty-nine samples from enucleated eyes with UM were analyzed. Fully-automated immunohistochemistry with polyclonal antibody anti-CD109 was performed. Sections of cutaneous melanoma were used as positive controls. The stained slides were analyzed by two experienced pathologists, who evaluated extension (1=focal and 2=diffuse) and intensity (0=negative, 1=weak, 2=strong) of staining. A score was obtained for each tumor by adding extension and intensity grades. Statistical analysis was performed using Mann-Whitney test to assess group differences regarding cell type, presence of liver metastasis and metastasis-free survival.
Results :
Of the 39 samples, 36 stained positive for CD109. The samples were divided into two groups according to cell type: 6 spindle (15.4%) and 33 epithelioid cell type (84.6%). The average score for spindle cell tumors was 1.8 and the average for epithelial cell tumors was 2.5. Intensity of staining was not significant between the two tumor types, but a trend showed decreased intensity in spindle tumors (P=0.07). A similar result was obtained when comparing extent of staining between the two groups (P=0.09). There was no correlation between CD109 staining and presence of liver metastasis (P=0.664). In addition, there was no significant correlation regarding CD109 staining and metastasis-free survival (P=0.809).
Conclusions :
The majority of UM tumors expressed CD109. There was a trend toward higher extent and intensity of expression in epithelioid cell tumors. This finding indicates a possible correlation between the expression of CD109 and more aggressive tumor phenotype.
To the best of our knowledge, this is the first investigation into CD109 expression in UM. Future studies with larger sample sizes are warranted.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.