Abstract
Purpose: :
Gene expression profiling (GEP) of melanocytic uveal tumors had been shown to be the most accurate predictor of metastatic disease that has been reported to date. The purpose of this study was to determine whether there is any relationship between GEP classification and thickness of melanocytic uveal tumors sampled by fine needle aspiration biopsy (FNAB).
Methods: :
Samples from 44 melanocytic uveal tumors were obtained by FNAB. Each sample was analyzed by GEP for the presence of the Class 1 (favorable) versus Class 2 (unfavorable) expression signature. The relationship between GEP classification and tumor thickness was evaluated by cross tabulation analysis and independent groups t testing.
Results: :
Tumor thickness ranged from 1.8 to 12.0 mm (mean = 5.6 mm, std. dev. = 2.8 mm). The pre-FNAB clinical diagnosis was choroidal melanoma in 29 cases, ciliary body melanoma in 10, and choroidal nevus versus melanoma in 5. Sixteen tumors were ≤ 3.5 mm thick, 16 were between 3.5 and 7 mm thick, and 12 were > 7 mm thick. Twenty five tumors were categorized as Class 2 by GEP while 19 were categorized as Class 1. Four of the 16 tumors ≤ 3.5 mm thick (25%), 8 of 16 tumors between 3.5 and 7 mm thick (50%), and 7 of 12 tumors > 7 mm thick (58.3%) were Class 2. Mean thickness of the 25 Class 1 tumors was 4.6 mm (SD = 2.5 mm) while that of the 19 Class 2 tumors was 6.9 mm (SD = 2.7 mm). This difference is statistically significant (t test, P = 0.006).
Keywords: melanoma • gene/expression • oncology