Cancer begins with a series of genetic changes that prompt a group of cells to overreplicate and then invade surrounding tissue, the point at which true malignancy begins.

• 癌症始于一连串的遗传变化，导致一群细胞繁殖过度，然后它们会侵犯邻近组织，此时肿瘤才真正开始转为恶性。