Article presentation

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.

Underline principals in the sage methodology:

• Serial analysis of gene expression (SAGE) is a powerful tool that allowsdigital analysis of overall gene expression patterns.

• A short sequence tag (10-14bp) contains sufficient information touniquely identify a transcript provided that the tag is obtained from aunique position within each transcript

• Sequence tags can be linked together to from long serial molecules thatcan be cloned and sequenced

• Quantitation of the number of times a particular tag is observed providesthe expression level of the corresponding transcript.

SAGE flowchart

SAGE ≠MICROARRAY• SAGE – An open system which detects both known and unknown

transcripts and genes.

SAGE library

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.

Results:

1. Identification of differentially expressed SAGE tags in GBC.

NOT COMPLETE

2. CTGF is overexpressed in microdissected primary GBC but

not in metastatic tissues.

3. CTGF protein is overexpressed in GBC and correlates with

improved survival.

Fig. 3. Immunohistochemistryfor CTGF protein expression in GBC and nonneoplasticgallbladder 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,representativeexamples of GBC with high CTGF expression.

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