The intrinsic radiosensitivity and sublethal damage repair capacity of five cervical carcinoma cell lines tested with the 96-well-plate assay.

We have tested the intrinsic radiosensitivity and capacity for sublethal damage repair (SLDR) in split-dose experiments with the 96-well plate clonogenic assay. Four out of five cell lines were squamous-cell carcinoma (SCC) lines (CaSki, ME-180, HX151c, HX156c) and one cell line was established from glassy-cell carcinoma (UM-GCC-1). Comparison of radiosensitivities was by with D value, the mean inactivation dose. D for these cell lines varied from 1.7 Gy to 2.5 Gy. As a group, cervical carcinoma cell lines were more radioresistant than endometrial adenocarcinoma cell lines tested with the same assay, but more radiosensitive than vulvar SCC lines. Three cell lines showed clear SLDR, but two cell lines were unable to carry out this function. Furthermore, cell lines capable of SLDR also showed significant increase in survival when D values were compared after the radiation dose was split into three instead of two fractions. These results indicate the importance of adding another radiobiological parameter to the intrinsic radiosensitivity when predictive tests are planned.