Multiple genetic aberrations including evidence of chromosome 11q13 rearrangement detected in pituitary adenomas by comparative genomic hybridization

Object. This study was conducted to determine whether comparative genomic h ybridization (CGH) is a more sensitive method for detecting genetic aberrat ions than other tests currently in use. Methods. The authors used CGH to examine 40 primary and 13 recurrent adenom as obtained from 52 patients for loss and gain of genetic material. Copy nu mber aberrations (CNAs) were detected in 25 (48%) of the 52 patients studie d. The chromosomes affected were, in order of decreasing frequency, 11, 7, X, 1, 8, 13, 5, 14, 2, 6, 9, 10, 12, 3, 18, 21, 4, 16, 15, 19, 22, and Y. E ndocrinologically active adenomas were more likely to contain (p = 0.009) a nd had a greater number (p = 0.003) of CNAs. Of 26 adenomas with CNAs, 18 s howed multiple aberrations involving entire chromosomes or chromosome arms. The most frequent CNA involving a chromosome subregion, which was present in four (8%) of 53 adenomas, was the loss of all chromosome 11 material exc ept for a preserved common segment containing 11q13. Immunoperoxidase stain ing did not detect cyclin D1 expression in those four cases, making cyclin D1 an unlikely target of this rearrangement. Conclusions. These findings indicate that genetic abnormalities are present in pituitary adenomas at a higher rate than previously reported, are assoc iated with endocrinological activity, and often involve several chromosomes . Rearrangement at 11q13 may inactivate a tumor suppressor gene or activate an oncogene that is important in the initiation or progression of sporadic pituitary adenomas.