IL-7 expression by NSCLC bone invading cells in mouse and human biopsies. A strong IL-7 level expression is shown by tumor cells in invaded bone (A). In contralateral bone, IL-7 level expression is detectable on stromal cells and it is lower than in bone invaded by tumor cells (B). In human biopsies, IL-7 is highly expressed by bone invading cells (C). Magnification 100×.