It requires processing a patient's own immune cells in a lab and returning them through the veins.

它需要在实验室中处理患者自己的免疫细胞，然后通过静脉将它们输回患者体内。

But when a genetic change disrupts this process cells begin to grow and divide uncontrollably thereby becoming cancer.

但是当基因改变打乱这个进程时，细胞就开始不受控制地生长和分裂，从而形成癌症。