16q loss of heterozygosity and microsatellite instability in Wilms' tumor.
OBJECTIVE
Wilms' tumor is the most common renal malignancy of childhood. Loss of heterozygosity (LOH) at 16q is seen in about 17% of cases and has been associated with a poor prognosis. To more precisely define the pattern of 16q deletion exhibited by Wilms' tumor, the authors performed a detailed LOH analysis of 96 specimens using polymorphic microsatellite repeat markers. The authors also evaluated the neoplasms for the presence of microsatellite instability (MSI).


METHODS
A total of 96 DNA samples were studied using polymerase chain reaction-based LOH analyses amplifying polymorphic microsatellite repeat markers. Screening for MSI using 2 additional genetic markers also was carried out.


RESULTS
The authors found 16q LOH in 14 of the specimens evaluated. Comprehensive analysis of these LOH-positive specimens showed a region of loss spanning 16p11.2-q22.1 and a separate distal region of LOH at 16q23.2-24.2. The distal region of deletion is very small, estimated to be approximately 2.4 megabases. In addition to the observed LOH, 2 specimens were found to consistently exhibit MSI, which has not been reported previously in Wilms' tumor.


CONCLUSIONS
The smallest consensus region of deletion in our analysis of Wilms' tumor 16q LOH measures 2.4 megabases at 16q23.2-q24.2. Additionally, MSI was present in a subset of tumor specimens suggesting that defects in DNA mismatch repair may contribute to the pathogenesis of Wilms' tumor.
Mason
J E
JE
Department of Surgery, Washington University School of Medicine, St Louis, Missouri, USA.
Goodfellow
P J
PJ
Grundy
P E
PE
Skinner
M A
MA
D002648:Child; D002872:Chromosome Deletion; D002885:Chromosomes, Human, Pair 16; D005819:Genetic Markers; D006801:Humans; D007680:Kidney Neoplasms / Q000235:genetics*; D019656:Loss of Heterozygosity; D018895:Microsatellite Repeats / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D009396:Wilms Tumor / Q000235:genetics*
D005819:Genetic Markers