- The document discusses gallbladder carcinoma (GBC), which has a low 5 year survival rate. GBC incidence varies by ethnicity and gender. Highest rates are seen in Mapuche Indian females. - Serial analysis of gene expression (SAGE) allows digital analysis of overall gene expression patterns through sequencing of short sequence tags from unique positions in transcripts. SAGE can detect both known and unknown transcripts. - The study used SAGE to analyze gene expression in GBC samples from three ethnic groups. Differentially expressed tags were identified. Connective tissue growth factor (CTGF) was found to be overexpressed in primary GBC but not metastatic tissues, and higher CTGF protein levels correlated with improved survival.

1. Article presentation

2. Introduction:
• Gallblader carcinoma (GBC) is the second most common malignancy of
the hepatobiliary system, 5 year survival is < 15%.
• Worldwide incidence of GBC are growing, mojority of case were observed
in Sauth America, Far Eastern and Southeast Asia and Eastern Europe.
• GBC incidence were highly correspond with ethnical background and
gender basis.
• Highest cases have been observed in female from Native American Indian
background (‘‘Mapuche Indian’’). However most cases of GBC are
diagnosed at advance level.
• Understanding molcular pathogenesis using SAGE technology enable to
identify molecular target for early detection of GBC.

3. Underline principals in the sage methodology:
• Serial analysis of gene expression (SAGE) is a powerful tool that allows
digital analysis of overall gene expression patterns.
• A short sequence tag (10-14bp) contains sufficient information to
uniquely identify a transcript provided that the tag is obtained from a
unique position within each transcript
• Sequence tags can be linked together to from long serial molecules that
can be cloned and sequenced
• Quantitation of the number of times a particular tag is observed provides
the expression level of the corresponding transcript.

5. SAGE flowchart

6. SAGE ≠MICROARRAY
• SAGE – An open system which detects both known and unknown
transcripts and genes.

7. SAGE library

8. Materials and methods:
• Three GBC samples were obtained from Hispani/Latino (‘‘H’’), Mapuche
Indian (‘‘M’’) and Caucasian (‘‘C’’).
• One gallbladder was obtained from Hispani/Latino women (“N”)
undergoing gastrectomy for gastric cancer.
• Total RNA were obtained from all four sample.
• L-SAGE libraries were constructed with NlaIII as a anchoring enzyme and
MmeI as tagging enzyme.
• The cancer Genome Anatomy Project “SAGE Tag Extraction Tool” was
used to extract SAGE tags.

9. Results:
1. Identification of differentially expressed SAGE tags in GBC.
NOT COMPLETE

10. 2. CTGF is overexpressed in microdissected primary GBC but
not in metastatic tissues.

12. 3. CTGF protein is overexpressed in GBC and correlates with
improved survival.
Fig. 3. Immunohistochemistry
for CTGF protein expression
in GBC and nonneoplastic
gallbladder mucosa. A,
absent/low CTGF expression
in normal gallbladder
epithelium. B, absence of
negative labeling in pyloric
metaplasia (PM), with CTGF
expression in associated
gallbladder dysplasia (DY). C
and D,representative
examples of GBC with high
CTGF expression.

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