Technical Report No. 2-86
Sensitivity to radiation of human normal, hyperthyroid, and neoplastic thyroid epithelial cells in primary culture
Miller RC, Hiraoka T, Kopecky KJ, Nakamura N, Jones MP, Ito T, Clifton KHEditor’s note: A publication based on this report was published in Radiat Res 111:81-91, 1987.
Summary
Samples of thyroid tissue removed surgically from 63 patients were cultured in vitro and X-irradiated to investigate the radiosensitivities of various types of thyroid epithelial cells. A total of 76 samples were obtained, including neoplastic cells from patients with papillary carcinoma (PC) or follicular adenoma (FA), cells from hyperthyroidism (HY) patients, and normal cells from the surgical margins of PC and FA patients. Culturing of the cells was performed in a manner which has been shown to yield a predominance of epithelial cells. Results of colony formation assays indicated that cells from HY and FA patients were the least radiosensitive: when adjusted to the overall geometric mean plating efficiency of 5.5%, the average mean lethal dose D0 was 97.6 cGy for HY cells, and 96.7 cGy and 94.3 cGy, respectively, for neoplastic and normal cells from FA patients. Cells from PC patients were more radiosensitive, normal cells having an adjusted average D0 of 85.0 cGy and PC cells a significantly (p=.001) lower average D0 of 74.4 cGy. After allowing for this variation by cell type, in vitro radiosensitivity was not significantly related to age at surgery (p=.82) or sex (p=.10). These results suggest that malignant thyroid cells may be especially radiosensitive.
Samples of thyroid tissue removed surgically from 63 patients were cultured in vitro and X-irradiated to investigate the radiosensitivities of various types of thyroid epithelial cells. A total of 76 samples were obtained, including neoplastic cells from patients with papillary carcinoma (PC) or follicular adenoma (FA), cells from hyperthyroidism (HY) patients, and normal cells from the surgical margins of PC and FA patients. Culturing of the cells was performed in a manner which has been shown to yield a predominance of epithelial cells. Results of colony formation assays indicated that cells from HY and FA patients were the least radiosensitive: when adjusted to the overall geometric mean plating efficiency of 5.5%, the average mean lethal dose D0 was 97.6 cGy for HY cells, and 96.7 cGy and 94.3 cGy, respectively, for neoplastic and normal cells from FA patients. Cells from PC patients were more radiosensitive, normal cells having an adjusted average D0 of 85.0 cGy and PC cells a significantly (p=.001) lower average D0 of 74.4 cGy. After allowing for this variation by cell type, in vitro radiosensitivity was not significantly related to age at surgery (p=.82) or sex (p=.10). These results suggest that malignant thyroid cells may be especially radiosensitive.