1. Genetic testing for high-risk colon cancer patients1
William M. Grady 
Gastroenterology 
Volume 124, Issue 6, Pages (May 2003)
DOI: /S (03)

2. Figure 1
Schematic diagram of the gene structure of APC with disease phenotypes associated with mutations in different regions of APC shown. The functional domains of the protein encoded by APC are indicated below the diagram. The exons in the gene are indicated by the numbers in the gene diagram. The black arrows in the mutation hotspots section indicate 2 of the most commonly observed mutations, 5-base pair deletions, and the white arrow indicates the location of a nucleotide polymorphism in the Ashkenazi Jewish population (I1307K) that is associated with colon cancer. AFAP, attenuated familial adenomatous polyposis; CHRPE, congenital hypertrophy of the pigmented retina epithelium. (Reprinted with permission from Grady WM, Markowitz SD. Colorectal cancer: genetic alterations. In: Kelsen DP, Daly JM, Kern SE, Levin B, Tepper JE, eds. Gastrointestinal oncology: principles and practice. Philadelphia: Lippincott Williams & Wilkins, 2002:687.
Gastroenterology  , DOI: ( /S (03) )

3. Figure 2
Schematic diagram of the protein truncation test for APC gene mutations. (A ) Genomic DNA extracted from blood is used to perform this assay. The APC gene or part of the APC gene (usually exon 15) is amplified in segments using polymerase chain reaction primers with “T7 handles,” which is the T7 promoter sequence that is used to initiate transcription by the T7 RNA polymerase. The polymerase chain reaction products are then subjected to in vitro reverse transcription followed by in vitro translation using 35S-labeled methionine to label the in vitro protein products. The labeled protein products are then analyzed by electrophoresis on a sodium dodecyl sulfate/polyacrylamide gel with a 10%–20% gradient and visualized using autoradiography. (B) A schematic figure showing representative results from a protein truncation test assay. The in vitro protein product from a normal subject will run at the expected size. The protein product from a person with a mutant APC allele that has a nonsense mutation will run at a smaller size because it is truncated. An individual with a mutant APC allele will also have a wild-type allele and will thus generate 2 protein products with this assay. Of note, a missense mutation in APC will not be detected by the protein truncation test assay because it will not cause the protein to be truncated.
Gastroenterology  , DOI: ( /S (03) )

4. Figure 3 Suggested algorithm for the molecular diagnosis of HNPCC.
Gastroenterology  , DOI: ( /S (03) )

5. Figure 4
(A ) Schematic diagram of method for assessing MSI. (B) Representative example of MSI analysis at TGF-β BATRII and D2S147. MSI is most commonly shown by a polymerase chain reaction-based method that generates labeled polymerase chain reaction products amplified from different microsatellite loci (e.g., D2S147). The labeled polymerase chain reaction products are subjected to polyacrylamide gel electrophoresis and then visualized. The unstable loci are identified because of their size difference from the loci in normal tissue. In the example, the polymerase chain reaction product has been end labeled with 32P-γ adenosine triphosphate and visualized with autoradiography. The microsatellite-unstable loci are recognized by their size difference from the normal tissue loci and are marked by arrows in the D2S147 locus figure.
Gastroenterology  , DOI: ( /S (03) )