生物体各种组织以细胞内蛋白合成的特异型式而显示各自的特异性分化。当正常细胞向癌转化,在形态未出现可见变化前,先有分子水平的变化。在癌变过程中,分子从高级逆转向低级幼稚状态变化。乳酸脱氢酶(LDH)的同功酶分布是这类逆转的一种标志。在多数恶性肿瘤,LDH 同功酶由 LDH_I 逐渐转向 LDH_V。这种变化见于肿瘤处,也见于同一器官有肿瘤趋向的较远离的组织。 Various tissues of the organism show their specific differentiation in the specific pattern of intracellular protein synthesis. When normal cells transform into cancer, there is a change in the molecular level before there is a visible change in morphology. In the process of carcinogenesis, the molecules change from high-grade reversal to low-grade naive state. The isoenzyme distribution of lactate dehydrogenase (LDH) is a sign of this type of reversal. In most malignancies, LDH isoenzymes gradually shift from LDH_I to LDH_V. This change is seen at the tumor site and is also seen in the more distant tissues of the same organ where the tumor tends.