Abstract
Purpose :
Deleted in Liver Cancer-1 gene (DLC1) encodes a Rho GTPase-activating protein 7 that participates in signaling pathways that regulate cytoskeletal changes. It was first described as a tumor suppressor gene in hepatocellular carcinoma and later described in several other tumors. Recently, DLC1 deletion in squamous cell carcinoma from the head and neck area has been reported. The aim of this study is to evaluate a possible role of DLC1 expression in the development and progression of ocular surface squamous neoplasia (OSSN).
Methods :
Seven normal human eyes (NHE) obtained from the Eyebank of Canada and 68 OSSN, including 18 papillomas (Pa), 21 conjunctival intraepithelial neoplasia (CIN) I, 11 CIN II, 7 CIN III, and 11 squamous carcinoma (sqCA) were evaluated by immunohistochemistry against DLC-1, using an automated immunostaining protocol. The German immunoreactive score (IRS [0-12] = intensity [0-3] x extension [0-4]) was used to evaluate staining. The Student's t-test and analysis of variances (ANOVA) with Tukey post-hoc test were used to compare mean IRS between groups.
Results :
DLC1 was expressed in all NHE (IRS=3.0±1.8), papillomas (IRS=5.6±3.1), CIN I (IRS=5.1±3.1), CIN II (8.3±3.3), CIN III (11±1.7) and SqCA (IRS=10.1±2.9). Furthermore, the IRS in the high grade lesions group (CIN II, III and SqCA) was significantly higher than the normal conjunctiva, Pa and CIN I group (ANOVA; P<0.0001). However, no IRS differences were noted within the low grade group (CIN I, papillomas or NHE) or within the high grade group.
Conclusions :
To the best of our knowledge this is the first study of DLC1 expression in OSSN. DLC1 is highly expressed in high grade squamous conjunctival neoplastic processes. DLC1 may act as an oncogene rather than a tumor suppressor, as opposed to squamous cell carcinoma of the head and neck region, and may play a role in OSSN pathogenesis development.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.