Monitoring translocations by M-FISH and three-color FISH painting techniques: a study of two radiotherapy patients.
OBJECTIVE
To compare translocation rate using either M-FISH or FISH-3 in two patients treated for head and neck cancer, with a view to retrospective dosimetry.


METHODS
Translocation analysis was performed on peripheral blood lymphocyte cultures from blood samples taken at different times during the radiotherapy (0 Gy, 12 Gy and 50 Gy) and a few months after the end of the treatment (follow-up).


RESULTS
Estimated translocation yield varied according to the FISH technique used. At 50 Gy and follow-up points, the translocation yields were higher with FISH-3 than with M-FISH. This difference can be attributed to three events. First, an increase in complex aberrations was observed for 50 Gy and follow-up points compared with 0 Gy and 12 Gy points. Second, at the end of treatment for patient A, involvement of chromosomes 2, 4, 12 in translocations was less than expected according to the Lucas formula. Third, a clone bearing a translocation involving a FISH-3 painted chromosome was detected.


CONCLUSIONS
More translocations were detected with M-FISH than with FISH-3, and so M-FISH is expected to improve the accuracy of chromosome aberration analyses in some situations.
Pouzoulet
F
F
Institut de Radioprotection et de Sûreté Nucléaire, Laboratoire de Dosimétrie Biologique, Fontenay aux Roses, France.
Roch-Lefèvre
S
S
Giraudet
A L
AL
Vaurijoux
A
A
Voisin
Pa
P
Buard
V
V
Delbos
M
M
Bourhis
J
J
Voisin
Ph
P
Roy
Laurence
L
D000368:Aged; D020223:Chromosome Painting / Q000379:methods*; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000532:radiotherapy*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008297:Male; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014178:Translocation, Genetic / Q000235:genetics* / Q000528:radiation effects*