Radiosensitivity of human normal and tumoral thyroid cells using fluorescence in situ hybridization and clonogenic survival assay.
OBJECTIVE
By using cell survival as a reference, we evaluated the radiosensitivity of human normal and tumoral thyroid cells using of radiation-induced translocations.


METHODS
Tissue samples were obtained from patients undergoing thyroidectomy. Cell cultures were established, irradiated with 60Co, and metaphases painted using commercial whole-chromosome 4 hybridization probe and pancentromeric probe. The clonogenic survival was assessed by conventional colony forming assay.


RESULTS
After irradiation, normal cultured thyroid cells yielded a higher number of translocations than cultures derived from adenomas or thyroid carcinoma. The colony forming assay demonstrated, by way of the mean inactivation dose, a higher survival of thyroid carcinoma and adenoma cells than of normal thyroid cells. This difference between tumoral and nontumoral cells is significant in each method (p = 0.0001), and cannot be explained by apoptosis in irradiated malignant cells. Correlation of the results obtained by both methods is shown by comparing the survival fraction at 2 Gy (SF2) and the percentage of chromosome 4 translocations at 2 Gy.


CONCLUSIONS
These results indicate that the yield of radiation-induced translocations serves as a good and rapid prediction of the intrinsic radiosensitivity of thyroid cells, and that this test could be applied to other tumors.
Gaussen
A
A
Service de Médecine Nucléaire, Institut Gustave-Roussy, Villejuif, France.
Legal
J D
JD
Beron-Gaillard
N
N
Laplanche
A
A
Travagli
J P
JP
Caillou
B
B
Parmentier
C
C
D000236:Adenoma / Q000235:genetics / Q000473:pathology*; D002277:Carcinoma / Q000235:genetics / Q000473:pathology*; D002470:Cell Survival; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D011836:Radiation Tolerance; D011853:Radiobiology; D013961:Thyroid Gland / Q000166:cytology / Q000528:radiation effects*; D013964:Thyroid Neoplasms / Q000235:genetics / Q000473:pathology*; D014407:Tumor Cells, Cultured / Q000528:radiation effects