Abstract
Purpose: :
To determine whether there is a relationship of iris color to gene expression profile (GEP) class in patients with posterior uveal melanoma.
Methods: :
A nonrandomized retrospective review was performed on a sequential series of newly diagnosed, untreated patients who underwent fine needle biopsy and GEP testing of posterior uveal melanoma during 2009 and 2010 in a private ocular oncology practice. GEP classification was based on the method developed by Dr. William Harbour and available as the DecisionDX-UM assay (Castle Biosciences). Two classes where determined by GEP; patients were either Class 1 (low risk for metastasis) or Class 2 (high risk for metastasis). Iris color was determined using slit lamp biomicroscopy and digital photography. Iris color was classified into two groups 1) dark, defined as uniformly brown in pigmentation; or 2) light, defined as blue, hazel, or green in pigmentation. Statistical analysis used a one-tailed Z-test for two proportions.
Results: :
A total of 25 patients with newly diagnosed, untreated posterior uveal melanoma were evaluated with both GEP and iris color classification. In this total group, GEP Class 1 (low risk) incidence was 16/25 (64%) and GEP Class 2 (high risk) incidence was 9/25 (36%). Dark iris incidence was 7/25 (28%); light iris incidence was 18/25 (72%). All 7/7 (100%) of dark irides were classified as GEP Class 1 (low risk). One half (9/18) of the light irides were found to be in GEP Class 1 (low risk), with the other half in GEP Class 2 (high risk). Although a small sample size, the differences between dark and light iris color association with GEP class were found to be statistically significant.
Conclusions: :
Dark colored irides appear to be associated with a greater incidence of low-risk GEP classification in contrast to light colored irides which appear to have a higher incidence of high-risk GEP classification. These results suggest that iris color may be a useful clinical prognostic indicator to estimate risk of developing metastatic disease in patients with posterior uveal melanoma.
Keywords: tumors • uvea • gene/expression