In 1997, a Johns Hopkins research team found an inherited genetic mutation called APC I1307K. APC, or adenomatous polyposis coli, is a gene that suppresses tumor growth. If the APC gene is defective, it makes the gene unstable and more susceptible to additional changes that may lead to colorectal cancer.
The APC I1307K mutation is primarily found in people of Ashkenazi Jewish heritage (Jews of Eastern European or Russian ancestry). Researchers believe that 6 percent of Ashkenazi Jews carry this gene mutation, making them at a significantly higher risk for developing colorectal cancer.
Chromosome 5 showing APC I1307K. (Click to Enlarge)
APC I1307K Symptoms
Many patients with colorectal cancer experience no symptoms in the early stages. In fact, symptoms may not appear until the disease is in advanced stage. Routine colorectal screening is very important. Even children from 11 years of age should be screened if there is a family history of colorectal cancer.
Many symptoms of colorectal cancer are also symptoms of other colon diseases. Therefore, it is important to see an experienced gastroenterologist who can perform the necessary tests and make an accurate diagnosis.
Symptoms you may experience include:
Blood in stool
A long period of constipation
Decrease in size of stool
Feeling of distension of abdomen (gas pain, bloating, fullness, cramping)
Unexplained weight loss
Vomiting and lethargy
APC I1307K Diagnosis at Johns Hopkins
If you are of Ashkenazi Jewish descent, your doctor may recommend that you get a genetic test to look for this gene mutation.
Learn more about diagnosing APCI1307K.
Genetic testing is a simple blood test. The test for APC I1307K only scans for that particular gene mutation; it does not look for gene mutations that cause other forms of colorectal cancer.
Before having a genetic test, you must undergo genetic counseling at our Colon Cancer Risk Assessment Clinic. This appointment will help you consider the many issues involved in genetic testing and understand how testing will affect you.
Johns Hopkins is one of the few laboratories in the country that performs the gene test for APC I1307K.
Testing for the APC I1307K Mutation: Are You a Candidate?
You should consider genetic testing if you are of Ashkenazi Jewish heritage and have a family history of colorectal cancer or polyps. Family history is defined as having at least one close family member with cancer or polyps. Ashkenazi Jews without a family history of colorectal cancer may still wish to be tested.
You can make an appointment with a member of the Johns Hopkins medical team or speak to someone at the Colorectal Cancer Risk Assessment Service at 410-614-LIFE (5433).
Positive Test Result for APC I1307K
If your test is positive for the genetic mutation, experts recommend:
If you do not already have colon cancer or polyps : Routine colonoscopy every two years, beginning at age 35, or five to 10 years before the earliest age at which cancer or polyps occurred in your family.
If you have a personal history of colon cancer or polyps : Routine colonoscopy every two years, or more often if your doctor recommends it.
It is important to detect polyps or cancer early. Treatment is more successful when cancer is caught at an early stage.
Our team will keep a detailed record of your medical history, which will include your personal and family history. A thorough physical examination will be performed and laboratory tests may be ordered. A digital rectal examination, which is a painless examination of your rectal area, may also be performed. Your doctor inserts a gloved, lubricated finger into the rectum to gently feel for any abnormalities.
Fecal Occult Blood Test
This test looks for occult (hidden) blood in the stool. For this test:
You receive three small cards and place a sample on each from three consecutive bowel movements.
A small amount of the stool is placed on a special test strip.
The stool is analyzed to check for blood.
A flexible sigmoidoscopy is a type of endoscopic diagnosis. An endoscope is a thin, flexible lighted tube that your doctor inserts inside you to see the rectum and lower colon.
During the procedure:
Your colon must be clear of stool so there is good visibility during the test. Preparations may include a liquid diet, enema and laxatives.
Your doctor inserts the sigmoidoscope through the rectum and into the anus and large intestine. This area is checked to see if cancer or polyps are present.
Your doctor may insert biopsy forceps through the scope in order to remove a small sample of tissue for further analysis. The procedure may cause some cramping or discomfort.
A colonoscopy is the best way to detect polyps or cancer, as it reaches further into the bowel than the sigmoidoscopy. That way we can determine if polyps or cancer are present.
During a colonoscopy:
Your colon must be clear of stool so your doctor has good visibility. Preparations may include a liquid diet, enema and laxatives.
You are sedated before the procedure.
Your doctor inserts the colonoscope through the rectum and into the anus and large intestine, and checks to see if cancer or polyps are present.
A biopsy forceps may be inserted through the scope in order to remove a small sample of tissue for further analysis.
If a polyp is found, it can be removed through the colonoscope.
The procedure may cause some cramping or discomfort.
A barium enema is an X-ray of the rectum and colon. Before the procedure, you will need to clear your colon of any stool. Preparations may include a liquid diet, enema or laxative. During a barium enema:A barium preparation (contrast material) is inserted through a rectal tube.
The barium outlines the colon, highlighting any abnormalities.
An X-ray is taken.
If polyps or cancer is present, those abnormalities can be visualized.
APC I1307K Treatment at Johns Hopkins
Treatment for APC I1307K varies. If your doctor found cancer during the examination, he or she will recommend colorectal surgery. Learn more about APCI1307K treatment at Johns Hopkins.