[ RadSafe ] Chernobyl Legacy Sheds Light On Link Between Thyroid Cancer And Radiation Exposure

[John Jacobus]

As I reread and rethink what is reported, I am not
impressed by the findings. It is clear that the BRAF
gene is the only cause of thyroid cancer. It is not
found in 42 per cent of adult cancers. So, I would say
that another genetic marker that is radiation
sesnsitive is still possible. Of course, the may not
be any correlation between thyroid cancer and
radiation based on the ref rearrangement as those who
deny radiation effects postulate.

Are there any reports of thyroid cancer detection
rates before and after the Chernobyl accident? I know
the absolute discoveries went up, but what was the
detectection rate.

--- radsafe-bounces at radlab.nl
<royherren2005 at yahoo.com> wrote:
> 
> Source:
> 
> Federation of European Cancer Societies
> 
>  
> 
> Date:
> 
> 2005-11-03
> 
>  
> 
>  
> 
> ---------------------------------
> 
> Chernobyl Legacy Sheds Light On Link Between Thyroid
Cancer And Radiation Exposure
> Paris, France, Tuesday 1 November 2005 - Study
results presented at the 13th European Cancer
Conference (ECCO 13) have provided further valuable
insights into certain genetic mutations which occur in
childhood thyroid tumours and their link to both
radiation exposure and patient age. 
> 
> The unique circumstances of this study were provided
for by the legacy of the radioactive accident at
Chernobyl Nuclear Power Plant in April 1986. Exposure
to radioactive fallout led to a large increase in the
incidence of papillary thyroid cancer (PTC), which was
particularly pronounced in those who were children at
the time of the accident. In normal circumstances,
thyroid cancer is rare in children under the age of
sixteen. 
> 
> The Chernobyl Tissue Bank was established in 1998 to
collect biological samples from those aged under 19 at
the time of the accident who subsequently developed
thyroid tumours and were resident in the areas of
Ukraine and Russia contaminated by the radioactive
iodine (131-I) fallout. Radioactive iodine 131-1 has a
short half-life of seven days and quickly dissipates
in the environment. The investigators were aware of
the fact that the incidence of thyroid cancer had
dropped down to normal occurrence rates in those
children born 9 months after the Chernobyl accident.
The continued collection of material by the Tissue
Bank gave the investigators a unique opportunity to
compare the samples gathered from children who
experienced the Chernobyl accident with those born
nine months after the incident whose thyroid cancers
were unlikely to arise from exposure to 131-I. 
> 
> The overall aim of the study was to compare the
genetic mutations found in childhood thyroid cancer
sufferers born before and after the accident -- and
assess the link to radiation exposure or patient age
at diagnosis. Overall, 52 cases of PTC were studied,
using tissue obtained from the Chernobyl Tissue Bank.
These cases were split into four groups matched
according to age, sex and place of residence. Two
groups of 13 cases were from the areas of Ukraine most
heavily contaminated with radioiodine -- one group of
13 born before the accident and the other born after
the 1st January 1997, and therefore spared exposure to
radioiodine. The two other groups of 13 cases were
from other areas of the Ukraine which were not exposed
to significant radioiodine fallout -- again consisting
of one group of children with PTC born before the
accident and one group born after 1st January 1987. 
> 
> Molecular biology studies found no difference with
respect to type or overall frequency of a particular
genetic mutation, known as ret rearrangement, between
any of the groups -- despite the fact that ret
rearrangement had been thought to be a potential
marker of radiation exposure. This study therefore
shows that, contrary to other reports in the
literature, there is no association between ret
rearrangement and radiation exposure. Rather, the
study investigators believe that the real link between
the patterns of molecular biological alterations
observed post-Chernobyl in thyroid cancer might
actually be related to the age of the patients under
study, rather than radioiodine exposure. Only one
child out of the 52 studied had a specific gene
mutation, known as BRAF, which is typically present at
higher levels in adult thyroid cancer sufferers. In
contrast, 58% of adult thyroid cancer patients in the
Ukraine show this mutation. 
> 
> Overall, the insights provided by the study of
Chernobyl children with thyroid cancer suggest that
age at diagnosis of cancer should be taken into
account before drawing conclusions about any link
between the specific molecular biology of the cancer
and radiation exposure -- as this may actually have
more significance. 
> 
> Principle study inve
=== Message Truncated === 


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On Oct. 5, 1947, in the first televised White House address, President Truman asked Americans to refrain from eating meat on Tuesdays and poultry on Thursdays to help stockpile grain for starving people in Europe. 

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com


	
		
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