The heterogeneous distribution of monosomy 3 in uveal melanomas: implications for prognostication based on fine-needle aspiration biopsies.
BACKGROUND
The detection of monosomy 3 in uveal melanomas has repeatedly been associated with adverse outcome. Fine-needle aspiration biopsy is being used to detect monosomy 3 in these tumors, based on the assumption that this chromosomal abnormality is distributed homogeneously throughout the tumor.


OBJECTIVE
To study the distribution of monosomy 3 in primary uveal melanoma by fluorescence in situ hybridization (FISH).


METHODS
We studied 50 enucleated eyes with uveal melanoma. In all 50 tumors we performed cytogenetic analysis and FISH using a DNA-specific probe for the centromere region of chromosome 3 on cultured tumor cells. In addition, the percentage of tumor cells with monosomy 3 was assessed by FISH on nuclei, isolated from paraffin-embedded tissue and compared to results of FISH on regular histology sections of the paraffin-embedded tissue.


RESULTS
Combining karyotyping and FISH on cultured cells identified monosomy 3 in 19 (38%) of 50 tumors, whereas FISH on nuclei isolated from paraffin-embedded tissue showed 31 (62%) of 50 as having monosomy for chromosome 3. FISH analysis on paraffin sections showed tumor heterogeneity for copy number of chromosome 3 in at least 7 cases.


CONCLUSIONS
FISH analysis on paraffin sections shows that heterogeneity of monosomy of chromosome 3 is a frequent phenomenon in uveal melanoma. FISH on nuclei isolated from paraffin-embedded tissue identifies a higher frequency of monosomy 3 than the traditional combination of karyotyping and FISH on cultured uveal melanoma cells. The practice of assigning patients to risk categories based on fine-needle aspiration biopsy samples from primary uveal melanoma may be subject to error based on the heterogeneous distribution of monosomy 3 in these tumors.
Maat
Willem
W
Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.
Jordanova
Ekaterina S
ES
van Zelderen-Bhola
Shama L
SL
Barthen
Ed R
ER
Wessels
Hans W
HW
Schalij-Delfos
Nicoline E
NE
Jager
Martine J
MJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D044963:Biopsy, Fine-Needle; D002467:Cell Nucleus / Q000235:genetics; D002869:Chromosome Aberrations; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008545:Melanoma / Q000235:genetics* / Q000473:pathology; D008875:Middle Aged; D009006:Monosomy / Q000235:genetics* / Q000473:pathology; D016612:Paraffin Embedding; D011379:Prognosis; D014407:Tumor Cells, Cultured; D014604:Uveal Neoplasms / Q000235:genetics* / Q000473:pathology
D014408:Biomarkers, Tumor