[Association of clinical and morphological tumor characteristics with the status of chromosomes 1, 3, and 8 in iris melanoma].

UNLABELLED: There is only a limited number of studies devoted to the molecular genetic status of patients with iris melanoma.

PURPOSE: This study aimed to analyze the frequency of chromosomal aberrations in tumor tissue in patients with iris melanoma.

MATERIAL AND

METHODS

Data from 140 patients with uveal melanoma (UM) treated between 2006 and 2023 were analyzed. Group A included 48 patients with iris melanoma, group B - 62 patients with iris melanoma with extension into the ciliary body. Group C (comparison group) consisted of 30 patients with choroidal melanoma treated in 2012. Subsequently, patients were divided into four subgroups according to chromosomal alterations. Additional subgroups with combinations of two or more aberrations were also identified. All tumors were histologically verified.

RESULTS

The spindle cell tumor type was observed significantly more frequently in the 1p+8p subgroup (A) compared with the M3+1p subgroup (A) (p<0.05), whereas the mixed cell type was more common in the M3+1p subgroup (A) than in the 1p+8p subgroup (A) (p<0.05). A significant association was found between the frequency of partial monosomy of chromosome 3 and mixed cell and epithelioid cell tumor types (p<0.05) in the partial M3 subgroup (C). In iris melanoma, deletion of the entire short arm of chromosome 1 was detected in 68.7% of cases and of chromosome 8 in 47.9%; in tumors with extension into the ciliary body, this was observed in 77.4% and 51.6% of cases, respectively, whereas in choroidal melanoma - in 30% and 20% of cases, respectively.

CONCLUSION

The present study showed for the first time that deletions of the short arms of chromosomes 1 and 8 are detected 2.5 times more frequently, and monosomy of chromosome 3 occurs 1.5 times less frequently in iris melanoma compared to choroidal melanoma. The revealed features confirm the more favorable biological behavior of iris melanomas compared to choroidal melanomas.