Background: Chromosomal alterations play an
important role in carcinogenesis. Enhanced
chromosomal radiosensitivity is shown for many
cancer predisposition conditions including breast
cancer. In this study chromosomal radiosensitivity
and the frequency of background sister chromnatid
exchanges (SCE) in lymphocytes of normal individuals
and breast cancer patients was compared. Materials
and Methods: G2 assay was performed on peripheral
blood lymphocytes obtained from 60 breast cancer
patients and 50 normal control. Blood culture was
initiated and cells were irradiated with 1 Gy gammarays
4 h prior to harvesting. After metaphase preparations
and slide making, chromatid aberrations were
scored. For SCE studies, blood samples from 30
breast cancer patients and 30 normal control were
studied. 24 hours after culture initiation, 5-
bromodeoxy uridine (BrdU) was added and cells were
harvested 48 hours after addition of BrdU. Slides
were stained in Hoechst 33258 and exposed to UVA
source, then stained in Giemsa. Results: Results
indicated that the frequency of radiation induced
chromatid breaks was significantly higher in breast
cancer patients compared to normal control
(p<0.01). From radiosensitivity point of view, 12% of
normal control and 47% of breast cancer patients
showed elevated chromatid radiosensitivity.
Frequency of background SCE was significantly higher
in lymphocytes of breast cancer patients compared to
lymphocytes of control (p<0.05). Conclusion:
Elevated chromosomal radiosensitivity and higher
frequency of SCE in lymphocytes of breast cancer
patients might be indicative of genomic instability of
these cells. Increased radiosensitivity could also be
due to defects in DNA repair genes involved in breast
cancer formation. Iran. J. Radiat. Res., 2011 9(3):
167-174
Mozdarani H, Ziaee Mashhadi A, Alimohammadi Z. G2 chromosomal radiosensitivity and background frequency of sister chromatid exchanges of peripheral blood lymphocytes of breast cancer patients. Int J Radiat Res 2011; 9 (3) :167-174 URL: http://ijrr.com/article-1-803-en.html