THE INTRINSIC RADIOSENSITIVITY AND SUBLETHAL DAMAGE REPAIR CAPACITY OF 5 CERVICAL-CARCINOMA CELL-LINES TESTED WITH THE 96-WELL PLATE ASSAY

We have tested the intrinsic radiosensitivity and capacity for subleth al damage repair (SLDR) in split-dose experiments with the 96-well pla te clonogenic assay. Four out of five cell lines were squamous-cell ca rcinoma (SCC) lines (CaSki, ME-180, HX151c, HX156c) and one cell line was established from glassy-cell carcinoma (UM-GCC-1). Comparison of r adiosensitivities was by with D value, the mean inactivation dose. D f or these cell lines varied from 1.7 Gy to 2.5 Gy. As a group, cervical carcinoma cell lines were more radioresistant than endometrial adenoc arcinoma cell lines tested with the same assay, but more radiosensitiv e than vulvar SCC lines. Three cell lines showed clear SLDR, but two c ell lines were unable to carry out this function. Furthermore, cell li nes capable of SLDR also showed significant increase in survival when D values were compared after the radiation dose was split into three i nstead of two fractions. These results indicate the importance of addi ng another radiobiological parameter to the intrinsic radiosensitivity when predictive tests are planned.