Gullick W J
ICRF Oncology Group, Hammersmith Hospital, London, U.K.
Prog Growth Factor Res. 1990;2(1):1-13. doi: 10.1016/0955-2235(90)90006-6.
The growth of normal breast epithelial cells is regulated by a complex interacting system of polypeptide factors and by steroid hormones. The cells respond to these factors through receptors which generate mitogenic and other intracellular signals. These second messengers provoke complex responses which may ultimately result in DNA replication and cell division. A comparison of normal cells and tumour cells, either in culture or from primary tumour biopsies, has revealed differences in growth factor and growth factor receptor expression. Such changes may represent aspects of the process of malignant transformation. In addition some evidence suggests that changes in second messenger systems may also occur. Finally several changes in nuclear oncogenes have been observed in breast cancers. It has been proposed that changes in the nuclear oncogenes, perhaps involving the loss of function of tumour suppressor genes, may allow cells to enter the cell cycle. Changes in growth factors, their receptors or intracellular second messenger systems may stimulate unregulated growth. The combination of these events provide a model for the process of carcinogenesis.
正常乳腺上皮细胞的生长受多肽因子和类固醇激素构成的复杂相互作用系统调控。细胞通过受体对这些因子作出反应，这些受体产生促有丝分裂和其他细胞内信号。这些第二信使引发复杂反应，最终可能导致DNA复制和细胞分裂。对培养中的正常细胞与肿瘤细胞或原发性肿瘤活检组织中的细胞进行比较，揭示了生长因子和生长因子受体表达的差异。此类变化可能代表恶性转化过程的某些方面。此外，一些证据表明第二信使系统也可能发生变化。最后，在乳腺癌中观察到核癌基因有若干变化。有人提出，核癌基因的变化，可能涉及肿瘤抑制基因功能的丧失，可能使细胞进入细胞周期。生长因子、其受体或细胞内第二信使系统的变化可能刺激不受调控的生长。这些事件的综合作用为致癌过程提供了一个模型。
