SIMPLE NUMERICAL CHROMOSOME-ABERRATIONS IN 2 PITUITARY-ADENOMAS

Cytogenetic analysis of short-term cultures of one non-secreting and o ne prolactin-producing pituitary adenoma revealed simple clonal numeri cal abnormalities in both tumors. The karyotype of the non-secreting a denoma was 48,XX, + 4, + 9[42]/49,XX, + 4, + 9, + 20[2]/46,XX[6]. In t he prolactin-secreting adenoma, three aberrant clones were detected, g iving the karyotype 45,X, - Y [20]/47,XY, +Y[6]/45,XY, - 21[3]/46,XY[2 1]. One cell had the chromosome complement 46.X, - Y, + 9; no other no nclonal aberrations were detected. The only hitherto published case of pituitary adenoma analyzed by banding techniques (Rey et al. [1986]: Cancer Genet Cytogenet 23:171-174) also had only numerical clonal chan ges that included extra copies of chromosome 9. We conclude that pitui tary adenomas may be karyotypically characterized by numerical aberrat ions and that trisomy 9 seems to be the best candidate for a primary c hromosomal anomaly.