Radiation-induced cancer cell repopulation: a possible mechanism implied by experiments using transplantable mouse-derived sarcoma cell line.

Purpose: Treatment with any cytotoxic agent can trigger surviving cells in a tumor to divide faster than before. This phenomenon is widely recognized as "repopulation". To better clarify the mechanism, gene expression profiling and pathological experiments were performed.

Novel function of transcription factor ATF5: blockade of p53-dependent apoptosis induced by ionizing irradiation.

Purpose: To find a new molecule that affects p53-dependent radiosensitivity.

Methods And Materials: A mouse sarcoma cell line, QRsP(p53+/+), was used. From this cell line, we established a radiosensitive clone and a radioresistant one.