Effects of MDM2, MDM4 and TP53 codon 72 polymorphisms on cancer risk in a cohort study of carriers of TP53 germline mutations.
BACKGROUND
Previous studies have shown that MDM2 SNP309 and p53 codon 72 have modifier effects on germline P53 mutations, but those studies relied on case-only studies with small sample sizes. The impact of MDM4 polymorphism on tumor onset in germline mutation carriers has not previously been studied.


RESULTS
We analyzed 213 p53 germline mutation carriers including 168(78.9%) affected with cancer and 174 who had genotypic data. We analyzed time to first cancer using Kaplan-Meier and Cox proportional hazards methods, comparing risks according to polymorphism genotypes. For MDM2 SNP309, a significant difference of 9.0 years in the average age of cancer diagnosis was observed between GG/GT and TT carriers (18.6 versus 27.6 years, P = 0.0087). The hazards ratio was 1.58 (P = 0.03) comparing risks among individuals with GG/GT to risk among TT, but this effect was only significant in females (HR = 1.60, P = 0.02). Compared to other genotypes, P53 codon 72 PP homozygotes had a 2.24 times (P = 0.03) higher rate for time to develop cancer. We observed a multiplicative joint effect of MDM2 and p53 codon72 polymorphism on risk. The MDM4 polymorphism had no significant effects.


CONCLUSIONS
Our results suggest that the MDM2 SNP309 G allele is associated with cancer risk in p53 germline mutation carriers and accelerates time to cancer onset with a pronounced effect in females. A multiplicative joint effect exists between the MDM2 SNP309 G allele and the p53 codon 72 G allele in the risk of cancer development. Our results further define cancer risk in carriers of germline p53 mutations.
Department of Epidemiology, University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
Shenying
S
Fang
Ralf
R
Krahe
Guillermina
G
Lozano
Younghun
Y
Han
Wei
W
Chen
Sean M
SM
Post
Baili
B
Zhang
Charmaine D
CD
Wilson
Linda L
LL
Bachinski
Louise C
LC
Strong
Christopher I
CI
Amos
D000293:Adolescent; D000328:Adult; D018797:Cell Cycle Proteins; D003062:Codon / Q000235:genetics; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D018095:Germ-Line Mutation / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D015999:Multivariate Analysis; D009369:Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*; D014481:United States / Q000453:epidemiology; D055815:Young Adult
D018797:Cell Cycle Proteins; D003062:Codon; C482775:MDM4 protein, human; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2