Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer
Aim:To assess the frequency and spectrum of chromosome aberrations and micronuclei in peripheral blood lymphocytes of patients with parotid salivary gland tumors and relapse of breast cancer during the course of neutron therapy. Materials and Methods: Samples of peripheral blood were obtained from 9...
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Інститут експериментальної патології, онкології і радіобіології ім. Р.Є. Кавецького НАН України
2012
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| Цитувати: | Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer / A.A. Melnikov, S.A. Vasilyev, L.I. Musabaeva, V.V. Velikaya, O.V. Gribova, Zh.A. Startseva, L.N. Urazova, I.N. Lebedev, E.L. Choynzonov // Experimental Oncology. — 2012. — Т. 34, № 4. — С. 354-357. — Бібліогр.: 19 назв. — англ. |
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irk-123456789-1398782018-06-22T03:04:54Z Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer Melnikov, A.A. Vasilyev, S.A. Musabaeva, L.I. Velikaya, V.V. Gribova, O.V. Startseva, Zh.A. Urazova, L.N. Lebedev, I.N. Choynzonov, E.L. Original contributions Aim:To assess the frequency and spectrum of chromosome aberrations and micronuclei in peripheral blood lymphocytes of patients with parotid salivary gland tumors and relapse of breast cancer during the course of neutron therapy. Materials and Methods: Samples of peripheral blood were obtained from 9 patients with parotid salivary gland tumors (T3N0–3M0) and 8 patients with relapse of breast cancer before, after first fraction and at the end of neutron therapy. The treatment course specified 5.5–8.4 Gy (equivalent to 23–44 Gy of photon irradiation) with 1.3–2.2 Gy per fraction for patients with parotid salivary gland tumors and 4,8–8.0 Gy (equivalent to 30–40 Gy of photon irradiation) with 1.6 Gy per fraction for patients with relapse of breast cancer. Control group established for conventional cytogenetic analysis consisted of 15 healthy persons. Assessment of chromosome aberrations frequency was performed on routinely stained metaphase plates. Lymphocytes from the same patients were analyzed by micronucleus test in combination with fluorescent in situ hybridization (FISH) using pancentromeric DNA probe. Results: Level of chromosome aberrations and micronuclei significantly increased in lymphocytes of patients from both groups during neutron therapy (P < 0.05). This increase was mainly due to chromosome-type aberrations and centromere-negative micronuclei. The prevalent types of aberrations are in agreement with theoretical mechanisms of neutron effects on cells. Conclusion: Cytogenetic effects of fast neutron therapy in lymphocytes of patients with parotid salivary gland tumors and relapse of breast cancer were observed. A positive dynamics of radiation-induced chromosomal damages formation during the course was denoted in lymphocytes of cancer patients in both groups. 2012 Article Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer / A.A. Melnikov, S.A. Vasilyev, L.I. Musabaeva, V.V. Velikaya, O.V. Gribova, Zh.A. Startseva, L.N. Urazova, I.N. Lebedev, E.L. Choynzonov // Experimental Oncology. — 2012. — Т. 34, № 4. — С. 354-357. — Бібліогр.: 19 назв. — англ. 1812-9269 http://dspace.nbuv.gov.ua/handle/123456789/139878 en Experimental Oncology Інститут експериментальної патології, онкології і радіобіології ім. Р.Є. Кавецького НАН України |
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Original contributions Original contributions |
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Original contributions Original contributions Melnikov, A.A. Vasilyev, S.A. Musabaeva, L.I. Velikaya, V.V. Gribova, O.V. Startseva, Zh.A. Urazova, L.N. Lebedev, I.N. Choynzonov, E.L. Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer Experimental Oncology |
| description |
Aim:To assess the frequency and spectrum of chromosome aberrations and micronuclei in peripheral blood lymphocytes of patients with parotid salivary gland tumors and relapse of breast cancer during the course of neutron therapy. Materials and Methods: Samples of peripheral blood were obtained from 9 patients with parotid salivary gland tumors (T3N0–3M0) and 8 patients with relapse of breast cancer before, after first fraction and at the end of neutron therapy. The treatment course specified 5.5–8.4 Gy (equivalent to 23–44 Gy of photon irradiation) with 1.3–2.2 Gy per fraction for patients with parotid salivary gland tumors and 4,8–8.0 Gy (equivalent to 30–40 Gy of photon irradiation) with 1.6 Gy per fraction for patients with relapse of breast cancer. Control group established for conventional cytogenetic analysis consisted of 15 healthy persons. Assessment of chromosome aberrations frequency was performed on routinely stained metaphase plates. Lymphocytes from the same patients were analyzed by micronucleus test in combination with fluorescent in situ hybridization (FISH) using pancentromeric DNA probe. Results: Level of chromosome aberrations and micronuclei significantly increased in lymphocytes of patients from both groups during neutron therapy (P < 0.05). This increase was mainly due to chromosome-type aberrations and centromere-negative micronuclei. The prevalent types of aberrations are in agreement with theoretical mechanisms of neutron effects on cells. Conclusion: Cytogenetic effects of fast neutron therapy in lymphocytes of patients with parotid salivary gland tumors and relapse of breast cancer were observed. A positive dynamics of radiation-induced chromosomal damages formation during the course was denoted in lymphocytes of cancer patients in both groups. |
| format |
Article |
| author |
Melnikov, A.A. Vasilyev, S.A. Musabaeva, L.I. Velikaya, V.V. Gribova, O.V. Startseva, Zh.A. Urazova, L.N. Lebedev, I.N. Choynzonov, E.L. |
| author_facet |
Melnikov, A.A. Vasilyev, S.A. Musabaeva, L.I. Velikaya, V.V. Gribova, O.V. Startseva, Zh.A. Urazova, L.N. Lebedev, I.N. Choynzonov, E.L. |
| author_sort |
Melnikov, A.A. |
| title |
Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer |
| title_short |
Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer |
| title_full |
Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer |
| title_fullStr |
Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer |
| title_full_unstemmed |
Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer |
| title_sort |
cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer |
| publisher |
Інститут експериментальної патології, онкології і радіобіології ім. Р.Є. Кавецького НАН України |
| publishDate |
2012 |
| topic_facet |
Original contributions |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/139878 |
| citation_txt |
Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer / A.A. Melnikov, S.A. Vasilyev, L.I. Musabaeva, V.V. Velikaya, O.V. Gribova, Zh.A. Startseva, L.N. Urazova, I.N. Lebedev, E.L. Choynzonov // Experimental Oncology. — 2012. — Т. 34, № 4. — С. 354-357. — Бібліогр.: 19 назв. — англ. |
| series |
Experimental Oncology |
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2025-07-10T09:17:50Z |
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2025-07-10T09:17:50Z |
| _version_ |
1837250981160550400 |
| fulltext |
354 Experimental Oncology 34, 354–357, 2012 (December)
CYTOGENETIC EFFECTS OF NEUTRON THERAPY IN PATIENTS
WITH PAROTID GLAND TUMORS AND RELAPSE OF BREAST
CANCER
A.A. Melnikov 1*, S.A. Vasilyev 2, L.I. Musabaeva 1, V.V. Velikaya 1, O.V. Gribova 1, Zh.A. Startseva1,
L.N. Urazova1, I.N. Lebedev 2, E.L. Choynzonov 1
1Cancer Research Institute, Siberian Branch of the Russian Academy of Medical Sciences, Tomsk 634050,
Russia
2Institute of Medical Genetics, Siberian Branch of the Russian Academy of Medical Sciences, Tomsk
634050, Russia
Aim: To assess the frequency and spectrum of chromosome aberrations and micronuclei in peripheral blood lymphocytes of patients
with parotid salivary gland tumors and relapse of breast cancer during the course of neutron therapy. Materials and Methods: Samples
of peripheral blood were obtained from 9 patients with parotid salivary gland tumors (T3N0–3M0) and 8 patients with relapse of breast
cancer before, after first fraction and at the end of neutron therapy. The treatment course specified 5.5–8.4 Gy (equivalent to 23–
44 Gy of photon irradiation) with 1.3–2.2 Gy per fraction for patients with parotid salivary gland tumors and 4,8–8.0 Gy (equivalent
to 30–40 Gy of photon irradiation) with 1.6 Gy per fraction for patients with relapse of breast cancer. Control group established for
conventional cytogenetic analysis consisted of 15 healthy persons. Assessment of chromosome aberrations frequency was performed
on routinely stained metaphase plates. Lymphocytes from the same patients were analyzed by micronucleus test in combination with
fluorescent in situ hybridization (FISH) using pancentromeric DNA probe. Results: Level of chromosome aberrations and micronuclei
significantly increased in lymphocytes of patients from both groups during neutron therapy (P < 0.05). This increase was mainly due
to chromosome-type aberrations and centromere-negative micronuclei. The prevalent types of aberrations are in agreement with
theoretical mechanisms of neutron effects on cells. Conclusion: Cytogenetic effects of fast neutron therapy in lymphocytes of patients
with parotid salivary gland tumors and relapse of breast cancer were observed. A positive dynamics of radiation-induced chromo-
somal damages formation during the course was denoted in lymphocytes of cancer patients in both groups.
Key Words: chromosome aberrations, micronucleus test, neutron therapy.
World-wide experience of past decades showed
that neutron therapy significantly increases the treat-
ment efficacy of patients with radioresistant head and
neck cancer and breast cancer due to higher damaging
effects of neutrons [1]. However, it is often hard to elimi-
nate the most radioresistant fraction of tumor cells
without crossing the border of healthy tissue tolerance
[2–4]. This may result in late adverse reactions to neu-
tron therapy and thus, require the development of new
effective approaches to assess the radiation damage
in healthy tissues of patient during neutron therapy.
Cytogenetic assessment is recommended by World
Health Organization, United Nations Scientific Com-
mittee on the Effects of Atomic Radiation and Interna-
tional Atomic Energy Agency as accurate and reliable
assay to indicate the radiation damage in human cells
[5]. Biological effects of ionizing radiation are the sum
of absorbed dose, dose distribution throughout the
body and individual radiosensitivity of the patient [6].
In addition, the issue of radiation-induced numeri-
cal chromosome aberrations in human cells remains
open today [8]. Data concerning the aneugenic effect
of radiation are insufficient and sometimes contra-
dictory to make a clear conclusion. This requires the
assessment of both structural and numerical chro-
mosome abnormalities for complete characterization
of radiation-induced effects in cells of cancer patients
during the neutron therapy. In addition to conven-
tional cytogenetic analysis of routinely stained meta-
phase plates cytokinesis-blocked micronucleus test
in combination with fluorescent in situ hybridization
(FISH) is used to assess the levels of both structural
and numerical chromosomal abnormalities in human
peripheral blood lymphocytes [9, 10]. Thus, the aim
of this study was to analyze the level and spectrum
of chromosomal aberrations and micronuclei in pe-
ripheral blood lymphocytes of patients with parotid
salivary gland tumors and relapse of breast cancer
during the neutron therapy.
MATERIALS AND METHODS
Patients. Samples of peripheral blood were
obtained from 9 patients with parotid salivary gland
tumors (T3N0–3M0) and 8 patients with relapse
of breast cancer before, 24 h after first fraction and
at the end of neutron therapy. Before entering the
study all subjects were informed about the aim and the
experimental details and gave their signed informed
consent. This study was approved by Bioethics Com-
mittee of Cancer Research Institute Siberian Branch
of the Russian Academy of Medical Sciences.
Therapy using 6.3 MeV fast neutrons was per-
formed on cyclotron U-120 at the Research Institute
of Nuclear Physics of Tomsk Polytechnic University.
The treatment course specified 5.5–8.4 Gy (equivalent
Received: October 23, 2012.
*Correspondence: E-mail: genetic87@sibmail.com
Abbreviations used: FISH – fluorescent in situ hybridization; LET –
linear energy transfer
Exp Oncol 2012
34, 4, 354–357
Experimental Oncology 34, 354–357, 2012 (December)34, 354–357, 2012 (December) (December) 355
to 23–44 Gy of photon irradiation) with 1.3–2.2 Gy per
fraction for patients with parotid salivary gland tumors
and 4.8–8.0 Gy (equivalent to 30–40 Gy of photon
irradiation) with 1.6 Gy per fraction for patients with
relapse of breast cancer. Two radiation field sizes were
used: 6 by 6 cm and 6 by 8 cm.
Control group. Control group established for con-
ventional cytogenetic analysis consisted of 15 healthy
persons.
Blood sampling. Samples of venous blood
(4 mL per each sampling time) were collected
in heparinized vacutainer tubes (Greiner, Austria).
Patients were sampled three times throughout the
study. Using blood samples collected before therapy,
individual baseline values for each test parameter
were done. The pre-treatment blood sample was col-
lected two hours prior to the first fraction of radiation.
The response of peripheral blood leukocytes to the
radiotherapy was evaluated on blood samples taken
after the application of the first dose, as well as after
the last received radiotherapy dose.
After venipuncture, the blood samples were coded
and transferred to laboratory. They were processed
immediately after transportation and cell cultures were
launched for the analysis of structural chromosomal
aberrations and the cytokinesis-block micronucleus
(CBMN) assay in combination with FISH following the
recommendations by International Atomic Energy
Agency and the HUMN project [11–13].
Chromosomal aberrations analysis. Chromo-
somal aberrations analysis was performed according
to International Atomic Energy Agency guidelines
[12]. In brief, cultures were incubated in vitro for
52 h in RPMI-1640 medium (Sigma, USA) with 10%
fetal bovine serum (Thermo Scientific, USA) and
stimulated by phytohaemagglutinin (PHA; PanEco
Russia). To arrest dividing lymphocytes in metaphase,
colchicine was added 2 h prior to the harvest. Prepara-
tions were made according to the standard procedure.
Slides were stained with 5% Giemsa solution (Sigma,
USA). All slides were coded and scored blindly at 1000´
magnification under oil immersion on microscope
“Axioskop” (Carl Zeiss, Germany). Structural chromo-
somal aberrations were classified based on the num-
ber of sister chromatids and breakage events involved.
Only metaphases containing 45–47 centromeres were
analyzed. Three hundred metaphases per sample per
each point of irradiation were analyzed.
CBMN assay in combination with FISH. CBMN
assay was performed using lymphocyte cultures
according to the standard protocol with minor modi-
fications [13]. Lymphocyte cultures were incubated
in RPMI-1640 medium for 72 h. Cytochalasin B was
added at 44 h in final concentration 5 µg/mL. Slides
were made according to the standard procedure.
FISH was performed with the use of pancentro-
meric DNA probe specific for the pericentromeric sat-
ellite DNA sequences of all human chromosomes [7].
A fluorescent label (TAMRA-dUTP) was incorporated
into the DNA probes using the standard nick-transla-
tion reaction [14]. The specificity of the resultant DNA
probes was estimated in normal human metaphase
plates. FISH was performed as described earlier [15].
Criteria proposed by M. Fenech et al. (2007)
for MN identification were used [11]. Altogether
1000 binuclear (BN) cells per each sample per point
of experiment were scored. Total number of MN and
their types were determined, along with the number
of micronucleated cells.
The nonparametric Wilcoxon matched pairs test
was used to statistically estimate the differences
of chromosomal aberrations and micronuclei levels
between various time points during radiation therapy.
RESULTS AND DISCUSSION
Frequency of aberrant metaphases before radia-
tion therapy was 0.32 ± 0.05% in the group of patients
with parotid salivary gland tumors and 1.62 ± 0.72%
in the group of patients with relapse of breast cancer.
No significant differences were observed in the mean
frequency of aberrant metaphases between patients
with parotid salivary gland tumors and healthy per-
sons (0.29 ± 0.14%, P = 0.69). However, significant
differences were found between patients with relapse
of breast cancer and control group (P = 0.012).
Frequency of micronuclei in groups of patients with
parotid salivary gland tumors (0.72 ± 0.05%) and with
relapse of breast cancer (1.12 ± 0.19%) was signifi-
cantly higher than in healthy persons (0.55 ± 0.04%,
P < 0.05) [9].
Frequency of all chromosomal aberrations in-
creased in the group of patients with relapse of breast
cancer from 2.01 ± 0.95% before the radiation
therapy to 3.13 ± 0.84% after the first irradiation and
to 4.65±0.91% at the end of treatment course (Ta-
ble 1). Significant increasing was observed also for the
frequencies of aberrant metaphases (P = 0.046), chro-
mosome-type aberrations (P = 0.017), atypical mono-
centrics (P = 0.027), paired fragments (P = 0.010),
centromere-negative micronuclei (P = 0.016) and sum
of all micronuclei (P = 0.01) only at the end of radiation
therapy in comparison with levels before the treatment.
In the group of patients with parotid salivary gland
tumors the frequency of all chromosomal aberra-
tions was significantly higher after the first fraction
(2.00 ± 0.31%) and at the end of neutron therapy
(3.01 ± 0.35%) in comparison with 0.32±0.15% before
the treatment (P < 0.05, Table 2). Opposite to the pa-
tients with relapse of breast cancer the frequency of all
chromosomal aberrations and micronuclei significantly
increased after the first fraction of the therapy and sub-
sequently till to the end of treatment course (Table 2).
Chromosome-type aberrations in peripheral blood
lymphocytes are known to be a specific biomarker
of ionizing radiation exposure [16–18]. As expected,
in our study chromosome-type aberrations prevailed
among detected abnormalities at the end of the neu-
tron therapy (97 and 95.5% in the groups of patients
with salivary gland tumors and with relapse of breast
cancer, respectively). In turn, the most frequent ab-
356 Experimental Oncology 34, 354–357, 2012 (December)
normalities among the chromosome-type aberrations
were paired fragments. This is not surprising because
of paired fragments formed both due to the lack of DNA
double-strand break repair and as a result of misrepair
together with chromosome translocations. More-
over, most of detected micronuclei did not contain
centromere (centromere-negative micronuclei) and
corresponded to acentric chromosomal fragments.
Table 1. Frequencies of chromosomal aberrations and micronuclei in pe-
ripheral blood lymphocytes of 8 patients with relapse of breast cancer dur-
ing neutron therapy (mean ± standard error, %)
Time point Before treat-
ment
After the 1st
fraction
At the end
of treatment
Dose range of neutron irradiation - 1.6 Gy 4.8–6.56 Gy
Equivalent dose range 25–35 Gy
Chromosome aberration analysis (routinely stained metaphase plates)
Number of analyzed metaphase
plates
2260 2440 2290
Aberrant metaphases 1.62 ± 0.72 2.68 ± 0.78 4.16 ± 0.77*
Total number of aberrations 2.01 ± 0.95 3.13 ± 0.84 4.65 ± 0.91
Chromosome-type aberrations 1.81 ± 0.86 3.03 ± 0.74 4.45 ± 0.75*
Paired fragments 1.01 ± 0.41 1.62 ± 0.43 2.74 ± 0.38*
Ring chromosomes 0.16 ± 0.12 0.25 ± 0.13 0.20 ± 0.08
Dicentric chromosomes 0.37 ± 0.22 0.45 ± 0.21 0.54 ± 0.26
Atypical monocentrics 0.08 ± 0.05 0.33 ± 0.14 0.75 ± 0.21*
Double-minute chromosomes 0.16 ± 0.11 0.37 ± 0.13 0.20 ± 0.14
Chromatid-type aberrations 0.21 ± 0.08 0.09 ± 0.09 0.21 ± 0.16
Chromatid breaks 0.16 ± 0.09 0.05 ± 0.05 0.21 ± 0.16
Isochromatid breaks 0.04 ± 0.04 0.04 ± 0.04 0
Micronucleus test (using pancentromeric DNA-probe)
Total number of micronuclei 1.24 ± 0.19 1.83 ± 0.06 3.48 ± 1.01*
Centromere-negative micronuclei 0.78 ± 0.16 1.44 ± 0.08 2.60 ± 0.88*
Centromere-positive micronuclei 0.46 ± 0.06 0.39 ± 0.08 0.88 ± 0.14
Nucleoplasmatic bridges 0.02 ± 0.01 0.04 ± 0.01 0.09 ± 0.03
Notes: *statistically significant differences in comparison with level before
treatment, P < 0.05
Table 2. Frequencies of chromosomal aberrations and micronuclei in pe-
ripheral blood lymphocytes of 9 patients with parotid salivary gland tumors
during neutron therapy (mean ± standard error, %)
Time point Before treat-
ment
After the 1st
fraction
At the end
of treatment
Dose range of neutron irradiation - 1.3–2.2 Gy 5.5–8.4 Gy
Equivalent dose range 23–44 Gy
Chromosome aberration analysis (routinely stained metaphase plates)
Number of analyzed metaphase
plates
2520 2550 2580
Aberrant metaphases 0.32 ± 0.05 1.80 ± 0.26* 2.69 ± 0.23*
Total number of aberrations 0.32 ± 0.15 2.00 ± 0.31* 3.01 ± 0.35*
Chromosome-type aberrations 0.15 ± 0.08 1.89 ± 0.26* 2.86 ± 0.29*
Paired fragments 0.08 ± 0.08 1.33 ± 0.28* 1.71 ± 0.23*
Ring chromosomes 0 0.03 ± 0.03 0.33 ± 0.19
Dicentric chromosomes 0 0.15 ± 0.08 0.15 ± 0.08
Atypical monocentrics 0 0 0.26 ± 0.07*
Double-minute chromosomes 0.07 ± 0.05 0.38 ± 0.20 0.40 ± 0.15
Chromatid-type aberrations 0.17± 0.07 0.11 ± 0.05 0.11 ± 0.06
Chromatid breaks 0.13 ± 0.07 0 0.07 ± 0.05
Isochromatid breaks 0.04 ± 0.04 0.11 ± 0.05 0.07 ± 0.05
Micronucleus test (using pancentromeric DNA-probe)
Total number of micronuclei 0.72 ± 0.05 1.28 ± 0.08* 1.87 ± 0.26*
Centromere-negative micronuclei 0.43 ± 0.56 0.97 ± 0.07 1.32 ± 0.19*
Centromere-positive micronuclei 0.29 ± 0.03 0.31 ± 0.04 0.55 ± 0.10
Nucleoplasmatic bridges 0 0.07 ± 0.03 0.10 ± 0.04
Notes: *statistically significant differences in comparison with level before
treatment, P < 0.05
On the contrary to the frequency of centromere-
negative micronuclei, the level of centromere-positive
micronuclei increased insignificantly after the neutron
therapy (Table 1, 2). Centromere-positive micronuclei
contain whole chromatid/chromosome(s) or centric
chromosome fragments and they are produced as a re-
sult of indirect radiation effects expressed less mark-
edly after exposure to high-LET radiation (including
neutrons). Therefore, significant increase of the levels
of acentric fragments, centromere-negative micronu-
clei and insignificant increase of centromere-positive
micronuclei are in agreement with the nature of fast
neutrons. Regarding to the importance of these chro-
mosomal malformations for the cell fate, loss of chro-
mosomal fragments or whole chromosome usually
leads to reduced viability of cells and decreased risk
of malignant transformation.
Translocations are two-hit chromosome aberra-
tions and could be detected by the analysis of routinely
stained metaphase plates as a dicentric chromosome
or monocentric chromosome with atypical appear-
ance (atypical monocentrics). Misrepair of radiation-
induced damage in the peripheral blood lymphocytes
of cancer patients in our study was observed as sig-
nificant increase of atypical monocentrics at the end
of neutron therapy in both groups (Table 1, 2). Also,
there was insignificant increase of dicentric chromo-
somes and corresponding nucleoplasmic bridges
during the radiotherapy. Cells with atypical monocen-
trics are viable and a number of specific chromosome
translocations are known to be a cause of leukemia
[19]. Increase of stable translocation level in the lym-
phocytes of cancer patients during neutron therapy
could possibly be a risk factor of radiation-induced
secondary cancer.
Thus, in our study for the first time we have ob-
served cytogenetic effects of fast neutron therapy
in lymphocytes of patients with parotid salivary gland
tumors and relapse of breast cancer. It was shown
that total increase of cytogenetic damages dur-
ing the treatment course is mainly due to formation
of chromosome-type aberrations. A positive dynamics
of the formation of radiation-induced chromosomal
damage in the course of neutron therapy was observed
in lymphocytes of cancer patients in both groups. Such
bioindication of cytogenetic abnormalities are believed
to be an important tool to assess the level of damage
in irradiated tissues and could be used with the aim
of optimization and individualization of the treatment.
ACKNOWLEDGEMENTS
The study is supported by the state contract
№ 16.512.11.2063 of Federal Target Research and
Technology Program of the Ministry of Education and
Science of Russian Federation, Federal Target Re-
search Program “Scientific and scientific-educational
personnel of innovative Russia (2009–2013)” (grant
№ 14.132.21.1319) and grant for young scientists of
“OPTEC” company.
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