SYNTACTIC STRUCTURE-ANALYSIS IN UVEAL MELANOMAS

Syntactic structure analysis was carried out successfully on 92 paraff in embedded uveal melanomas, taken from patients with a minimum follow up of 5 years. This simple, fast, and reproducible method of describi ng the tumour architecture has been significantly correlated with mali gnancy in tumours from several sites. Paraffin sections 5 mu m thick, were cut and stained with haematoxylin and eosin. Tumours were classif ied according to a modification of the Callender classification. A min imum spanning tree (MST), using the centre points of tumour nuclei, wa s constructed in five randomly chosen fields with an interactive digit ising video overlay system. Ten syntactic structure features were deri ved from each MST; subsequently, the mean and standard deviation of th e five fields analysed were calculated for further statistical analysi s. Reproducibility was acceptable with a mean correlation coefficient of 0.70. In univariate survival analysis, the percentage of points wit h three neighbours yielded prognostic significance (p<0.05). Minimum s panning tree variables were compared (chi(2) test) with classic tumour prognosticators and there was a significant correlation between Calle nder cell. type and the following MST parameters: mean number of point s (p<0.003); MST length (p<0.003); mean line length (p<0.01); number o f nuclei with one neighbour (p<0.004); number of nuclei with two neigh bours (p<0.02), and number of nuclei with three neighbours (p<0.005). Syntactic structure analysis is an evolving technique, but may be able to mathematically (and reproducibly) describe melanoma architecture a cross the spectrum of the Callender classes. This would also allow arc hitectural grading of tumours within the specific Callender groups, pr oviding more precise prognostic information. Further modifications of this technique are necessary to optimise prognostic potential when app lied to uveal melanomas.