Transcript colon cancer

COLORECTAL CANCER
Colorectal Cancer arises in
Epithelial cells outlining the
lumen of Colon & Rectum.
Epidemiology:
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Cancer is the 3rd cause of
ww.(6,3 million D/Y).
About 876,000 get CRC/Y.
About 525 000 CRC, D/Y.
Incidence Rate=15/ 100 000.
 CRC
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is the 3rd cancer killer after:
1 Lung Cancer > 2 Stomach.
death
COLORECTAL CANCER
 COLORECTAL POLYPS:
 Abnormal growths protruding
into the large intestine.
 Common condition in 20% of adults.
 Most polyps are benign.
 They produce no symptoms.
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SYMPTOMS OF CRC:
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Rectal Bleeding.
Change Of Bowel Habits.
Abdominal Pain, Discomfort.
Decreased Stool Diameter.
Weight Loss.
COLORECTAL CANCER
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How Are Polyps Diagnosed?
 Colorectal Endoscopy:
 1.
Colonoscopy.
 2. Sigmoidoscopy.
 Barium enema x-ray techniq.
 Fecal Occult Blood Test.
(FOBT)
Removal of polyps is advised.
 Colostomy is performed
for late stages.
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COLON CANCER
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As a result of accumulation of genetic alterations a polyp
(adenoma) is formed which turns into a cancer.
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A progression from early to intermediate to late adenoma to a carcinoma.
Staging System Characteristics
1: Degree of penetration
in the bowel wall.
 2: L.N. involvement.
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3: Distant metastases.
L.N. Involvement
Liver Metastases
Kidney Metastases
STAGING SYSTEM OF C.C.
 Astler-Coller:
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A: Tumor limited to mucosa,
B1: Tumor grows through
muscularis mucosae,
B2: Tumor grows beyond
muscularis propria,
C1: Stage B1 with regional
L.N. metastases,
C2: Stage B2 with regional
L.N. metastases,
D: Distant metastases.
GRADING SYSTEM OF C.C.
Grading: Normal
cells (differentiated)
 Cancer (less differentiated).
differentiation Faster growth & metastases.
 G1: Well differentiated,
 G2: Moderately well differentiated,
 G3: Poorly differentiated,
 G4: Undifferentiated.
 Less
THE CELL CYCLE
COLON CANCER
 P53
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gene : (TSG)
Located in the S.A. of
chromosome 17.
Code for phosphoprotein
that functions as T.F.
In respond to DNA damage
P53 protein expression is
increased, And regulates the
transcription of genes that
induce cell cycle arrest or
apoptotic cell death.
P53 mutation occurs in
80-90% of sporadic C.C.
COLON CANCER
 Adenom.
Polypopsi Coli (APC) gene:
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Located on L.A. of chromosome 5.
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APC protein plays a role in:
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regulation of apoptatic cell death;
Transfection of normal APC gene
into cell lines having 2 mutant
APC genes induces apoptosis.
Mutations on it occur on 50-80%
of sporadic colonic adenoma.
COLON CANCER
H19 Gene:
 An imprinted & developmentally regulated gene.
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Its product remains untranslated (oncofetal mRNA).
Expressed in tumors arising from tissues, which
express it in the fetal life.
Located on chromosome 11p15.5
To date, its function remains unknown.