Genomics and Applied Biology 2016, Vol.7, No.2, 1-7
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Tucker and Preston (Tucker and Preston, 1996) stated that for the frequency of the induced chromosome
aberration to be predicted accurately, cytogenetic evaluations should be made within a short time after the
treatment while the cells were undergoing their first mitotic division after the treatment. According to this
information, aberrations can be repaired in the second cell cycle and aberrations can be seen below their real
frequencies.Yoshioka et al. found, in a study they conducted, that radiation, a clastogenic agent, affected
mitochondrial DNA, ATP level and MN formation (Gül, 2005).
In a study which Aristei et al. conducted in 2009 on 20 women with breast cancer in early phase I and II
(individual and familial cancer patients were excluded from the study), they found an increase in SCE and MN
rates compared with the control group. In the same study, an increase was also observed in SCE frequency after
receiving chemotherapy (CT)
.
On the other hand, decreases were observed in SCE frequency in the same patient
group 6-12 months after CT (Stracci et al., 2009). However, smoking also causes increases in SCE frequency.
Increases were observed in MN frequencies in all patients after RT. Age is also correlated with MN frequency. In
this study, MN frequency in older patients exhibited a higher increase than in younger patients. This rate in the
patients can be related to the DNA repair mechanism (Kutbay, 2001).
In their study, Fenech and Morley reported that X-ray caused chromosomal damage in human lymphocytes and it
was an agent that affected aging (Kutbay, 2001).
In many studies, researchers reported that MN frequency increased in direct proportion to radiation dosage (Cole,
1981)
In a study they conducted in 1998, Sönmez et al. evaluated SCE in patients with Behcet’s disease and found
significant increases in SCE rate in the patient group in comparison with the control group (p<0.000 1). They
concluded that Behcet’s Disease could be related to genetic disorder and damage to DNA (Sönmez et al., 1998).
Sönmez et al. (1997) found increases in SCE frequencies in 15 patients with ankylozing spondylitis (Sönmez et al.,
1997).
In an in vivo study which Kasuba et al. conducted in 1999 on nurses who had been in contact with cytotoxic drugs
for long periods, no change was found in SCE increase whereas it was reported that the drug caused an increase in
MN frequency. An increase in MN was identified in nurses who had been in contact with drugs for long periods
compared with the control group. The fact that there was an increase in MN despite a lack of increase in SCE
indicated that MN analysis was a more sensitive technique than SCE analysis in mutagenic analyses (Gül, 2005).
Jakopin and Bilban (2001) applied mutageneity tests including chromosomal aberrations (CA), SCE and MN on
30 patients with Hodgkin’s disease after CT and RT treatment. They could not find significant differences between
the patients and the control groups before the treatment but after a 6-month treatment, they observed decreases in
CA, SCE and MN rates. However, when these rates were compared with the values right after the treatment, it
was found that they were not statistically significant. The researchers found significant differences in
micronucleus and chromosome aberration frequencies of patients who were treated with radiotherapy in
comparison with those who were treated with chemotherapy. When the treatment was completed 6 months later,
there was not complete recovery although mitotic activity was almost normal and chromosome damage was
observed. They attributed these changes to the possibility that in malignant diseases oncogenes may become
activated (Jakopin and Bilban, 2001). In this study,
a significant increase was observed in MN frequency in
patients in RT-b (p=0.005) and RT-c (p=0.005) groups compared with the control group. When RT-b was
compared with RT-a (p=0.001), a significant increase was observed in MN frequency. When RT-a and RT-c
measurements were compared, a statistically significant change was not observed. After a three-month treatment,
on the other hand, MN level dropped to pre-RT level. No difference was observed between the control groups and
the study groups in terms of BNC values. When RT-c and RT-b (p=0.001) groups were compared, a significant
decrease was observed in MN. On the other hand, no difference was observed between RT-a and RT-c in terms of
MN frequency (Table 1). The results of our study are in parallel with the results of other studies.
