Correlation of heterogeneity for chromosome 3 copy number with cell type in choroidal melanoma of mixed-cell type.
OBJECTIVE
To study heterogeneity for chromosome 3 copy number in mixed choroidal melanoma with discrete populations of spindle and epithelioid cells using chromosome in situ hybridization (CISH) and to correlate chromosomal loss with cell type.


METHODS
Twenty-two archival cases of choroidal melanoma with discrete populations of spindle and epithelioid cells were identified. CISH was used to identify chromosome 3 copy number in spindle and epithelioid areas.


RESULTS
Monosomy 3 was detected in 12 (55%) of 22 choroidal melanomas. Of these, 10 (45%) had two copies of chromosome 3 in both epithelioid and spindle cells, 7 (32%) showed monosomy 3 in the epithelioid areas only, and 5 (23%) showed monosomy 3 in both epithelioid and spindle areas.


CONCLUSIONS
CISH is a useful technique for analyzing chromosome copy number in different cell populations within a tumor. In mixed choroidal melanomas with discrete spindle and epithelioid cell populations, there may be heterogeneity for chromosome 3 copy number that correlates with areas of different cell type.
Sandinha
Teresa
T
Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, Scotland, United Kingdom.
Farquharson
Maura
M
McKay
Ian
I
Roberts
Fiona
F
D002830:Choroid Neoplasms / Q000235:genetics* / Q000473:pathology; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics*; D018628:Gene Dosage; D018740:Genetic Heterogeneity; D006801:Humans; D017403:In Situ Hybridization; D008545:Melanoma / Q000235:genetics* / Q000473:pathology; D009006:Monosomy