PT  - JOURNAL ARTICLE
AU  - TAKAHASHI, TAKEO
AU  - NAKANO, TAKASHI
AU  - OKA, KUNIYUKI
AU  - ANDO, KOICHI
TI  - Transitional Increase in Growth Fraction Estimated by Ki-67 Index After Irradiation to Human Tumor in Xenograft
DP  - 2004 Jan 01
TA  - Anticancer Research
PG  - 107--110
VI  - 24
IP  - 1
4099  - http://ar.iiarjournals.org/content/24/1/107.short
4100  - http://ar.iiarjournals.org/content/24/1/107.full
SO  - Anticancer Res2004 Jan 01; 24
AB  - The cell kinetics of human tumor cells (HSG) in vivo were estimated by Ki-67 index to analyze the biological behavior of quiescent cells after irradiation. The increment of Ki-67 index was dose-dependent up to 15 Gy irradiation. The Ki-67 index of tumor cells increased gradually from 35±5.0% before irradiation to 56±5.0% at day 5 after single irradiation of 15 Gy. Flow-cytometric study showed that the G1 population was decreased and the G2M population was elevated at day 5 after the irradiation. In fractionated irradiation, the time-course in the change of the Ki-67 index was similar to that of single irradiation. It was likely that tumor cells were recruited into the cell cycle from quiescent phase after irradiation. We consider the Ki-67 index to be a reliable indicator of growth fraction and useful to estimate the cell kinetics of irradiated tumors in vivo. The growth fraction estimated by Ki-67 index during radiotherapy is expected to be useful in predicting tumor response to radiation therapy.