Abstract
Purpose:
Although the incidence of uveal melanoma (UM) is low, it is the most common primary intraocular malignancy. In our previous study, we demonstrated that high percentage (47%) of UMs express the type-I receptor for Luteinizing Hormone-Releasing Hormone (LHRH-R). The gene encoding LHRH-R is harbored by chromosome 4q21.2, however the numerical aberrations of this chromosome 4 have never been studied by fluorescence in situ hybridization (FISH) in UM. In the present study, our aim was to investigate the copy number of chromosome 3, the monosomy of which has been implicated in the aggressive behavior of UM, and chromosome 4 in the same human UM samples.
Methods:
UM specimens were obtained from 46 patients at the time of enucleation at the Department of Ophthalmology, University of Debrecen, Hungary. Concomitant numerical aberrations of chromosome 3 and 4 were studied by FISH with centromere specific probes and the results analysed by D'Agostino-Pearson omnibus test and Spearman correlation.
Results:
Chromosome 4 could be detected in normal 2 copies only in 3 (6%) of our samples, while 33 cases (72%) showed more than 2 signals/nucleus. Two specimens showed monosomy for this chromosome. The presence of copy number alterations of chromosome 4 did not correlate with the presence of LHRH-R expression. Monosomy of chromosome 3 could be found in 16 (35%) samples. In 6 specimens (13%) we could detect more than 2 copies of chromosome 3.
Conclusions:
Based on our results, chromosome 4 is present in abnormal number in the majority of UMs. The rate of monosomy of chromosome 3 differs from that published in the literature (50%). This difference might be partially explained by the possibly diverse genetic background of the Hungarian population. According to our statistical analysis, there is a moderate (Spearman r=0.42; 0.139-0.639; CI=0.95%) but statistically significant (p=0.0036) correlation between the copy number of chromosome 3 and 4. Our results provide new information about the genetic background of this aggressive malignancy and could contribute to determine more precisely the prognosis and efficient therapeutic approaches of this malignancy.
Keywords: 589 melanoma •
539 genetics •
528 fluorescent in situ hybridization