X-chromosome loss of heterozygosity frequently occurs in gastrinomas and is correlated with aggressive tumor growth.
BACKGROUND
Recent studies have shown that tumor growth, rather than hormone overproduction, is the leading cause of death among patients with gastrinomas and other malignant gastrointestinal endocrine tumors. No patient/laboratory characteristics accurately predict which tumors will exhibit aggressive growth. Furthermore, little is known regarding the molecular pathogenesis of these tumors. X-chromosome loss of heterozygosity (LOH) occurs in some nonendocrine tumors, and its presence can be associated with aggressive growth/decreased survival. Data on X-chromosome LOH in gastrointestinal endocrine tumors are conflicting. Therefore, the purpose of the current study was to determine whether X-chromosome LOH occurred in gastrinomas and, if so, whether it was correlated with tumor growth, tumor behavior, and/or prognosis.


METHODS
X chromosome allelotyping was performed using 12 microsatellite markers spaced throughout the chromosome using DNA from leukocytes and microdissected gastrinoma specimens from 16 female patients. The presence of X-chromosome LOH was analyzed for correlations with clinical and laboratory tumor characteristics as well as tumor growth characteristics.


RESULTS
Nine gastrinoma specimens (56%) had X-chromosome LOH, ranging from 6% to 23% at the 12 different loci studied. X-chromosome LOH was significantly associated with aggressive postoperative tumor growth, increased primary tumor size, and pancreatic primaries. In 6 tumor specimens, LOH occurred on Xp22.1-22.3 over a 28.4-centimorgan region.


CONCLUSIONS
X-chromosome LOH was common in gastrinoma specimens from female patients, and its presence was found to be a potentially useful molecular/genetic prognostic factor for aggressive growth.
Chen
Yuan-Jia
YJ
Digestive Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Vortmeyer
Alexander
A
Zhuang
Zhengping
Z
Gibril
Fathia
F
Jensen
Robert T
RT
D000293:Adolescent; D000328:Adult; D041321:Chromosomes, Human, X / Q000235:genetics*; D004247:DNA / Q000032:analysis; D018572:Disease-Free Survival; D005260:Female; D015408:Gastrinoma / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D006801:Humans; D019656:Loss of Heterozygosity; D018895:Microsatellite Repeats; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D016133:Polymerase Chain Reaction; D015043:Zollinger-Ellison Syndrome / Q000235:genetics* / Q000473:pathology / Q000601:surgery
D004247:DNA