Navigation Links
Researchers discover atomic bomb effect results in adult-onset thyroid cancer

PHILADELPHIA Radiation from the atomic bomb blasts in Hiroshima and Nagasaki, Japan, in 1945, likely rearranged chromosomes in some survivors who later developed papillary thyroid cancer as adults, according to Japanese researchers.

In the September 1, 2008, issue of Cancer Research, a journal of the American Association for Cancer Research, the scientists report that subjects who lived close to the blast sites, were comparably young at the time, and developed the cancer quickly once they reached adulthood, were likely to have a chromosomal rearrangement known as RET/PTC that is not very frequent in adults who develop the disease.

"Recent in vitro and in vivo studies suggest that a single genetic event in the MAP kinase-signaling pathway may be sufficient for thyroid cell transformation and tumor development," said the study's lead author, Kiyohiro Hamatani, Ph.D., laboratory chief, Department of Radiobiology and Molecular Epidemiology at the Radiation Effects Research Foundation (RERF) in Hiroshima.

"Thyroid cancer is associated with exposure to external or internal ionizing radiation.Elucidation of mechanisms of radiation-induced cancer in humans, especially early steps and pathways, has potential implications for epidemiological risk analyses, early clinical diagnosis, and chemopreventive interventions," Hamatani said.

He adds that there are several irradiated populations worldwide that have been shown to have an increase in thyroid cancer, and that children exposed to radioactive fallout from the 1986 Chernobyl nuclear power plant accident who develop papillary thyroid cancer have also been found to have RET/PTC rearrangements, although they are slightly different.

This study is part of the foundation's long running follow-up research on 120,000 atomic bomb survivors. During 1958 to 1998, the study found about 470 thyroid cancer cases of which the estimated number of excess cases attributable to radiation is 63. About 90 percent of thyroid cancer among the survivors is of the papillary type.

Hamatani and colleagues from across Japan made a comparison between adult-onset papillary thyroid cancers with RET/PTC rearrangements and those with a BRAF mutation. More than 70 percent of adult onset papillary thyroid cancer in non-exposed patients is associated with mutations in the BRAF gene.

The researchers looked at the genetic profile of cancer patients in the RERF's follow-up study--50 patients who were exposed to atomic bomb radiation and 21 patients who were not. Three factors were found to be independently associated with the development of adult-onset papillary thyroid cancer with RET/PTC rearrangements. They were greater radiation dose, shorter time elapsed since radiation exposure, and younger age at the time of the bombings, Hamatani says.

"That means that a younger person living close to the bombing site would be more likely to have adult onset thyroid cancer having RET/PTC rearrangements," he said. "This is the first time this has been shown."

The findings also suggest that in childhood papillary thyroid cancer RET/PTC rearrangements may be much less clearly associated with radiation exposure, compared with adult-onset cancer, because RET/PTC rearrangements are frequent in childhood papillary thyroid cancer patients regardless of history of radiation exposure.

The researchers do not know exactly how radiation is involved in the occurrence of RET/PTC rearrangements. "It could be either by direct DNA damage or by other pathways such as a result of radiation-induced genomic instability," Hamatani said.


Contact: Jeremy Moore
American Association for Cancer Research

Related biology news :

1. Antidepressants need new nerve cells to be effective, UT Southwestern researchers find
2. Indiana U researchers launch social networking and research management tool for scientists
3. UC Davis researchers define characteristics, treatment options for XXYY syndrome
4. Munich researchers discover key allergy gene
5. Rapid test for pathogens developed by K-State researchers
6. OU researchers isolate microorganisms that convert hydrocarbons to natural gas
7. UH researchers win top prize for research with humanitarian applications
8. Caltech researchers awarded $10M for molecular programming project
9. Researchers study facial structures, brain abnormalities to reveal formula for detection of autism
10. Mount Sinai researchers discover technology that silences genes
11. Researchers link cocoa flavanols to improved brain blood flow
Post Your Comments:
(Date:4/28/2016)... First quarter 2016:   , Revenues amounted ... quarter of 2015 The gross margin was 49% (27) ... the operating margin was 40% (-13) Earnings per share ... operations was SEK 249.9 M (21.2) , Outlook   ... M. The operating margin for 2016 is estimated to ...
(Date:4/15/2016)...  A new partnership announced today will help ... in a fraction of the time it takes ... life insurance policies to consumers without requiring inconvenient ... Diagnostics, rapid testing (A1C, Cotinine and HIV) and ... weight, pulse, BMI, and activity data) available at ...
(Date:3/31/2016)... 2016   LegacyXChange, ... "Company") LegacyXChange is excited to release its ... to be launched online site for trading 100% guaranteed ... will also provide potential shareholders a sense of the ... an industry that is notorious for fraud. The video ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... 2016 , ... Newly created 4Sight Medical Solutions ... healthcare market. The company's primary focus is on new product introductions, to include ... are necessary to help companies efficiently bring their products to market. , The ...
(Date:6/27/2016)... BOSTON , June 27, 2016   Ginkgo ... biology to industrial engineering, was today awarded as ... a selection of the world,s most innovative companies. ... at scale for the real world in the ... organism engineers work directly with customers including Fortune ...
(Date:6/24/2016)... Brooklyn, NY (PRWEB) , ... June 24, 2016 , ... ... 15mm, machines such as the Cary 5000 and the 6000i models are higher end ... height is the height of the spectrophotometer’s light beam from the bottom of the ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... ... is pleased to announce the launch of their brand, UP4™ Probiotics, into Target ... over 35 years, is proud to add Target to its list of well-respected ...
Breaking Biology Technology: