FLUORESCENT IN-SITU HYBRIDIZATION ASSESSMENT OF CHROMOSOME COPY NUMBER IN GESTATIONAL TROPHOBLASTIC DISEASE

The concurrence of congenital trisomy 8 mosaicism and gestational trop hoblastic disease in a forty-two-year-old Gravida IV, Para IV female h as been described.(1) In contrast to other cases in the literature, th is patient had no additional confounding chromosomal abnormalities oth er than trisomy 8. To the best of our knowledge, this was the only rep orted case of constitutional trisomy 8 mosaicism associated with gesta tional trophoblastic disease, a rare gynecological disease entity in a nd by itself. The present report describes fluorescent in situ hybridi zation (FISH) studies for assessing chromosome 8 copy number on variou s patient tissues. The results of the FISH studies are compared with e ach other and with the original cytogenetic studies. It is concluded t hat the overall frequency of trisomy 8 cells is lower in the FISH stud ies using archival material than in the original conventional cytogene tic studies. This is true for the uterus and lung tissues with a metas tatic tumor. The possible reasons for the somewhat different frequenci es found between conventional cytogenetics via GTG-banding and interph ase cytogenetics via FISH are discussed.