DNA ploidy pattern in choroidal melanoma: correlation with survival. A flow cytometry study on archival material
- Paolo Totia,
- Giuseppe Grecob,
- Paola Mangiavacchia,
- Alessandra Brunia,
- Marie Louise Desirèe Palmeria,
- Pietro Luzia
- aInstitute of Pathological Anatomy and Histology, University of Siena, Siena, Italy, bDepartment of Ophthalmology and Neurosurgery, University of Siena, Siena, Italy
- Professor Pietro Luzi, Institute of Pathological Anatomy and Histology, University of Siena, Via delle Scotte, 53100 Siena, Italy.
- Accepted 15 April 1998
Abstract
BACKGROUND/AIMS Paraffin embedded samples have provided an important source of material for retrospective cytofluorimetric studies, useful in establishing the predictive value of DNA content measurements. The aim of this study was to investigate the incidence and type of aneuploidy in choroidal malignant melanomas (CMM) and the significance in the clinical outcome (median follow up 55 months).
METHODS DNA content was quantified by flow cytometry in 61 CMM from archival material. Non-tumour ocular tissue was used as the reference diploid standard. Cases in which the coefficient of variation (CV) of the diploid peak was >8% were excluded. The CMM were classified as spindle A, spindle B, mixed spindle and epithelioid, epithelioid, and necrotic.
RESULTS The frequency of the aneuploid DNA pattern was 38%. Necrotic tumours showed a worse clinical outcome independent of the ploidy pattern. Spindle A tumours were found to be diploid. Spindle B and mixed tumours showed a prevalent diploid and near diploid aneuploid pattern (DI <1.3), yet aneuploidy was not correlated with a worse prognosis. The epithelioid tumours were prevalently diploid. However, 83% of the aneuploid tumours were hypodiploid (DI <0.95), and showed the worst prognosis.
CONCLUSION These results indicate that increasing DNA abnormalities in CMM, especially in the epithelioid histotype, were associated with an increasing mortality.
