The Effect of A Low-Fat, High-Fiber, Fruit- and Vegetable-enriched Eating Plan on Colorectal Adenoma Recurrence: The Polyp Prevention Trial

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What are Microsatellites?
D2S123
TAGGCCACACACACACACACA
Unique Primer
Mono, di, tri, tetra nucleotide repeats HNPCC
- Expansion/contraction of nl repeats
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Strand Slippage
D2S123
14 bp
TAGGCCACACACACACACACA
13-15 BP
4-40 RPTS
Unique Primer
12 bp
TAGGCCACACACACACACACA
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Mis-Match Repair Genes
hMSH2 hMLH1 PMS1 PMS2 hMSH3 hMSH6
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Risk of CRC in ClinicalHNPCC Families
Netherlands
Sporadic
HNPCC
Age 44 69 Location pr
53 pr 32 ds 41 ds 68 CI35
10 .07 CI50 24 .5
CI75 42 5.3
Voskuil, Int J CA 199772205
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Risk of CRC in MSH2/MLH1HNPCC Families
Netherlands

CRC Lifetime 80 Women 83 Men 92 Endome
trial 50
Vasen, Gastro 19961101020
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HNPCC
90 of tumors show MI Germline defect in
MMR genes 2nd Hit - Somatic Mutation
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MSI in Sporadic CRC
10 - 15 of sporadic CRC In HNPCC
Germline somatic MSI Sporadic -
biallelic somatic mutation via methylation of
MLH1 promoter
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TC Transcription Complex
Click for larger picture
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Gene Testing for hMLH1 or hMSH2
DGGE SSCP IVSP Direct Sequencing
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Gene Testing
Cost ()
Sensitivity
Sequencing gt90 800 - 3,000 CSGE
Sequencing gt90 1500 Screening (SSCP)
95 - 100 800 Screening (PTT) 50 -
60 750 MSI NA 300
Gastro 2001121195
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Gene Testing for MSH2/MLH1
509 Finnish CRC pts

• 5/10 Founder mutation
• 7/10 Amsterdam Criteria
• All either young, had fam hx, or previous CA

63 MSI
10 (2) MMR mutations
Aaltonen, NEJM 1998381481
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Predictive Model for MMR Gene Testing
184 Kindreds 26 w/ MMR mutations 1) Mean age
at diagnosis of affecteds 2) At least 1 member
w/ Endometrial CA 3) Amsterdam Criteria
Wijnen, NEJM 1998339511
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Predictive Model for MMR Gene Testing
Logistic Model
Prob lt20
Prob gt20
MMR Analysis
MSI
-

MMR Analysis
Nothing
Wijnen, NEJM 1998339511
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Bethesda Criteria and MMR Mutation
N125, high risk, Frankfurt, GE
Total
BC
- BC
N 58 (46) 67 (54) 125 MSI 17 (29)
5 (7.5) 22 (18) MMR Mutation 11 (65) 0
(0) 11 (9) B1 - B4 46 (79)
Raedle, Ann Int Med 2001135566
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Bethesda vs. Amsterdam
MMR Mutation MSI status
Criteria to predict MSI
Spec
Sens
Amsterdam 6/6 27 94 Amsterdam
II 8/10 46 90 Bethesda
11/17 77 60
Raedle, Ann Int Med 2001135566
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Cost Effectiveness of MSI
Decision tree using MSI (Bethesda guidelines)
and MMR mutations 90 CI for
cost-effectiveness of screening patients with
cancer relatives 4,874 - 21,576 / life
year gained Sensitivity analysis - prevalence
HNPCC mutation 1 factor
Ramsey, Ann Int Med 2001135577
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Mutations in HNPCC Kindreds
32 Kindreds (N38) in Buffalo and Vermont
Amsterdam Criteria
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Incidence of Mutations MSH2/MLH1
Conclusion
Molecular basis unknown for many subjects
Weber, Cancer Res 1997573798
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Effectiveness of Screening in HNPCC
252 subjects, 22 Families (119 Control, 133
screen) Colon q3yrs, 1984, 15 yr F/U Not
randomized - declined participation
Screen
Control
OR
P
CRC 8 (6) 19 (16) .4 .01 Mutation
18 41 .4 .02 Deaths to CRC 0
8 lt.001
Jarvinen, Gastro 2000118
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Risk of Metachronous CRC
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Colonoscopy in High Risk Individuals
31 HNPCC Families - 232 Individuals 86 (38.6)
underwent colonos-compared to controls
Case Control P
CA 5 1 Adenomas 29 11
.03 TV/V () 11 1 Ad Diam
9.1 5.8 .02 HGD () 9 3
Ponz de Leon, CEBP 19987639
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Center for Families at Risk for CRC
Jan 98 - June 00
Goal To develop a registry of high risk
families To assemble blood/DNA for
research
Recruitment Physician referral, Media, UPCI CA
Registry
High Risk Definition Young onset, FDR young
onset, Multiple
cancers
Overall 83 individuals (76 families)
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UPCI Registry
188
Dead
Alive
106
82
Agreed
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26
23
Unavailable
Not Interested
11 (5.9)
Young onset cancers - lt45, 45-55
Enrolled
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High Risk Patients
70 Probands - Complete data, exclude FAP
67.1 High Risk
23 Young Onset (lt55) 9 Multiple CAs 15
Young and Multiple (8 Amsterdam Criteria)
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Problems With Center
Lab Support Integrated Recruitment
Coordinated Approach With Other Cancers
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Gene Testing
www.genetests.org www.nsgc.org