Abstract
Purpose: :
Genotyping using microsatellite markers is highly sensitive (92.8%) and specific (66.7%) for detection of aggressive uveal melanoma (UM). In the following study we investigated the utility of molecular genetic testing of the DNA extracted from routinely stained and processed smears from UM tumors.
Methods: :
Smears from five uveal melanoma cell lines and 12 primary tumors were prepared and stained with Papanicolaou and Romanowsky stains, two routine stains commonly utilized for cytological assessment of tumors. Genotyping was carried out utilizing 14 microsatellite markers on chromosomes 3, 6 and 8. Microsatellite markers were selected because they are currently more suitable for clinical molecular genetics laboratories than SNPs. Mutational screening for reported mutations in GNAQ and GNA11 genes was carried out by restriction fragment length polymorphism and direct sequencing. The results were compared to those obtained utilizing direct sequencing from frozen tumor tissues.
Results: :
High quality DNA was extracted from the stained slides with no difference in the efficiency of DNA extraction between the two staining techniques. DNA extracted was of sufficient quality for reproducible testing for allelic imbalances/loss of heterozygosity in chromosomes 3, 6p, 8q regions, as well as to study the common mutations in GNAQ and GNA11 genes.
Conclusions: :
We presented the feasibility of utilizing routinely stained cytology smears from UM for molecular genetic testing. This approach may eliminate the requirement for separate biopsies for pathological assessment and molecular testing, potentially reducing risk and ensuring the composition of the sample for molecular testing.
Keywords: melanoma • cytology • tumors