Irradiated tumor cells affect the growth of bystander tumor cells.

<p>Irradiated tumor cells mixed with bystander tumor cells were injected in mice. The tumor growth was monitored by tumor volume measurements (A) and images of representative mouse from each group are shown (B). B: bystander/unirradiated cells, R: irradiated cells. B: R (1:0): only bystander cells, B: R (0:1): only irradiated cells, B: R (1:1): bystander and irradiated cells in equal ratio. Data presented as mean ± SD (n = 10). *statistically significant than B: R (1:0) group at p<0.05. (C) Luc^-WEHI 164 cells irradiated with 15 Gy were mixed with unirradiated (bystander) Luc⁺WEHI 164 cells in an equal ratio. The tumor formation by bystander cells was monitored by in vivo imaging as shown in representative images. (D) Quantitative representation of difference in bioluminescence signal. B: mice injected with bystander cells (luciferase positive) only, B+R: mice co-implanted with bystander cells (luciferase positive) and irradiated Luc^-WEHI 164 cells. *statistically significant than B at p<0.05.