|DNA and Cancer|
Michael Guthrie, R. Ph.
Cancer is fundamentally genetic,
in that it arises from mutations distorting the information contained in
genes. For the most part, the genetic dysfunction is not inherited, but
acquired during life. In fact, probably less than 10% of cancer patients
have a strongly predisposing inheritance and another 20% to 30% have a
moderately predisposing inheritance (Ross, 1998).
All of this
genetics talk can become quite confusing, so we’ll try to keep it as
simple as possible. There is no doubt that some cancers are strongly
associated with a genetic predisposition…and let’s reemphasize the word
predisposition. Along with the predisposition, there almost always has
to be subsequent events that damage the DNA of a cell for that cell to
begin its course towards malignancy. In fact, the damage occurs with
specific genes that you will be hearing much more about:
proto-oncogenes, and tumor suppressor genes.
Tumor Markers: the
by: Michael Guthrie, R.
Most cancer patients are familiar with the term "tumor
marker." Such terms as PSA, CEA, CA-125, CA19-9 are thrown around by
oncologists quite frequently, but what exactly do these terms mean?
First of all, tumor markers are substances that can be detected
in elevated amounts in the blood, urine, or body tissues of
some patients with certain types of cancer.
Tumor markers are produced by cancer cells themselves, or by the body’s
response to cancer.
Tumor marker levels alone are
not sufficient to make a cancer diagnosis. Therefore, at
present, it is not possible to have a blood test to determine if one has
cancer. The National Cancer Institute lists at least four reasons why
this is so:
Surgery Alone as Effective as Surgery Plus
Radiotherapy to Treat Disease
Radiotherapy combined with
surgery appears to be no more effective than surgery alone in improving
survival rates of patients with locally advanced laryngeal
"During the past few years, radiotherapy (RT) has
been increasingly used in combination with surgery in the treatment of
locally advanced laryngeal carcinomas to improve survival rates in
patients with more extensive tumors," noted G. Cortesina and colleagues
from the University Turin in Italy.
Sigmoidoscopy May Miss Cancer
the most widely used fiber-optic screening exam for colon cancer, is
likely to miss diseased growths as much as one-third of the time,
researchers say in a study that could lead to wider use of a more
thorough method, colonoscopy.
The findings, along with a second
study reported in Thursday's New England Journal of Medicine, deepen
doubts about the reliability of sigmoidoscopy.
The Joy of Soy
This bland, unassuming little
bean and its by-products may not knock your taste buds out, but it
certainly packs a punch against certain forms of cancer, osteoporosis,
and heart disease, and it can ease the symptoms of menopause. Its lack
of flavor can actually serve as a big plus, allowing you to hide soy in
everything from milkshakes to chili. Your body will cheer while your
taste buds won't even notice it's there.
Pancreatic Cancer Detection
To document the
accuracy of magnetic resonance cholangiopancreatography (MRCP) in
differential diagnosis between pancreatic cancer and chronic
pancreatitis, researchers conducted a large prospective controlled
In all, 124 patients with an average age of 55 years and
a strong suspicion of pancreatic cancer were recruited for the study. A
radiologist and a gastroenterologist who were unaware of the clinical
diagnosis of patients interpreted the MRCP images. Exact diagnosis was
based on histological evidence from surgical and fine needle biopsy or a
follow-up of 12 months.