2008 Barcelona - European Society of Human Genetics

Cancer genetics
and another at another site . DNA from 175 patients with LC and 104
patients with MPT was analyzed using the single-strand conformation
polymorphism (PCR-SSCP) method and direct sequencing . We found
9 carriers of the p .I171V mutation among these 279 cancer patients
and only 1 carrier among 500 population controls (0 .2%) . Four carriers
of the p .I171V mutation were detected among 175 LC patients
(2 .3%) and 5 among 104 patients with MPT (4 .8%) . The frequencies
of the p.I171V mutation carriers in LC and MPT patients were significantly
higher than in controls (OR=11 .7, CI 1 .3-105 .2, p=0 .0175 and
OR=25 .2, CI 2 .9-218 .2, p=0 .0007; respectively) . In 1 individual with
LC, a novel molecular variant c.1222A>G (p.K408E) was identified.
No carriers of p .R215W or 657del5 NBS1 mutations were found in the
present study. These findings imply that heterozygous carriers of the
p .I171V mutation are prone to the development of larynx cancer and
may, in addition, display an increased risk of second tumors at other
sites .
P04.167
cpG island methylator phenotype in primary neuroblastomas is
associated with poor survival
E. Grau, S. Oltra, F. Martínez, C. Orellana, A. Canete, M. Hernandez, V. Castel;
Hospital Universitario La Fe, Valencia, Spain.
Hypermethylation of CpG islands (CGIs) is an epigenetic phenomenon
that contributes to carcinogenesis . We have determined the methylation
pattern of several genes involved in distinct biological pathways
in neuroblastoma (NB), one of the most common pediatric solid tumors.
82 primary NB tumors were studied by methylation specific PCR
(MSP) for twenty genes . Three of them were excluded (MGMT, SYK
and GSTP) because showed no evidence of promoter hypermethylation.
CpG island methylator phenotype (CIMP) status was defined as
hypermethylation of more than 50% from the 17 genes analyzed .
We found that some genes as TMS1, CASP8, THBS1, CCND2,
RASSF1A, BLU, EMP3 or DR4 are more frequently methylated in NB
cases with a poor prognosis. CIMP status was significantly associated
with disease stage (P=0,0002), risk group (P=0,00004), age at
diagnosis ((P=0,0007), N-myc amplification (P=0,005) and 1p deletion
(P=0,003) . By a Kaplan-Meier analysis, the 27 CIMP+ cases showed
significantly poorer disease-free survival (DFS) (P=0,0084) and overall
survival (OS) (P=0,0062) than the 55 CIMP- cases . However, Cox regression
analysis failed to demonstrate that CIMP was an independent
factor to the remaining variables, except for the clinical stage .
We conclude that CIMP status could strongly influence on OS in NB tumors,
being a better prognosis factor than the other high-risk variables
except for the disease stage . Thus the presence of CIMP may lead to
a poor prognosis by induction of CGIs methylation .
P04.168
DcX expression in bone marrow after induction correlates whit
reduced survival in high-risk neuroblastoma patients
S. Oltra, E. Grau, C. Orellana, F. Martinez, C. Fernandez, A. Cañete, V. Castel;
Hospital Universitario La Fe, Valencia, Spain.
Background: Detection of minimal residual disease (MRD) in bone
marrow (BM) and peripheral blood (PB) is crutial for follow-up in highrisk
neuroblastoma patients and might impact on survival .
Methods: Relative quantification of DCX and TH was studied by quantitative
reverse transcriptase polymerase chain reaction (QRT-PCR)
using Assays on Demand from Applied Biosystems (Oltra et al ., 2005,
Diagn Mol Pathol . 14: 53-57) . We studied DCX and TH expression in
87 high risk neuroblastoma patients (78 stage 4 and 9 stage 3) treated
according cooperative national protocols in Spain .
Results: The frequency of DCX and TH detection at diagnosis in BM
was 75,3% and 76,7% . After induction chemotherapy the frequency of
both markers decreased to 37,8% and 28,9% . In PB samples the frequency
of DCX and TH was 58,3% and 50%, respectively, at diagnosis
and 12,5% and 15,6% after induction .
Only the DCX expression in BM after induction chemotherapy showed
a statistically significant predictive value. Five years overall survival
(OS) and event-free survival (EFS) were significantly reduced in patients
with DCX expression in BM after induction (pC) in the 3’ UTR region has
been reported in association with breast and lung cancer risks .
This study was designed to investigate if polymorphism 8473T>C or
other polymorphisms in the 3’UTR region can contribute to NMSC after
transplantation . Genotyping of polymorphism 8473T>C in 150 patients
and 180 controls demonstrated no significant differences, also stratifying
by kind of tumor (p value>0 .2) . Moreover no appreciable difference
were noted in functional analysis to test influence of C or T variant.
Screening for new polymorphisms was performed in 30 NMSC and 30