Chromosomal aberrations in pituitary carcinoma metastases.

Four pituitary carcinoma metastases [two adrenocorticotropic hormone (ACTH) and prolactin cell tumors each] were studied by comparative genomic hybridization. Chromosomal gains were found in all four carcinoma metastases, but losses only in the two prolactin cell carcinoma metastases. Overall, pituitary carcinoma metastases showed an average of 8.3 chromosomal imbalances per tumor (7 gains vs 1.3 losses), 10 in prolactin cell carcinoma metastases (7.5 gains vs 2.5 losses) and 6.5 in ACTH cell carcinoma metastases (6.5 gains vs 0 loss). The most common changes were gains of chromosome 5, 7p, and 14q (in three tumors each). High-level gains were found on 13q22-qter and 14q (two cases each) and on 1q, 3p, 7, 8, 9p, and 21q (one case each). To date, gains of chromosome 14q have not been reported among pituitary tumors. It remains to be shown whether gain of 14q is associated with malignant progression and metastatic dissemination of pituitary carcinomas.