肿瘤细胞生物-中南大学.ppt

重要事实 癌症是一个全球主要的死亡原因：2007年，癌症死亡人数达790万（约占所有死亡人数的13%）。 肺癌（140万死亡） 胃癌（86.6万死亡） 肝癌（65.3万死亡） 结肠癌（67.7万死亡） 乳癌（54.8万死亡） 癌症及癌细胞的基本特征 肿瘤发生机制 原癌基因和抑癌基因 肿瘤标志物 肿瘤的治疗 癌症及癌细胞的基本特征 癌症是一组可影响身体任何部位的多种疾病的通称，又称为恶性肿瘤和赘生物。 细胞快速、异常生长 超越其通常边界生长、可侵袭身体的毗邻部位和扩散到其它器官。这一过程被称之为转移（metastasize） 。 肿瘤发生机制 癌症由一个单细胞变异造成。 这种变异可由外部因子和遗传基因因素造成。 从一个正常细胞转变为一个肿瘤细胞要经过一个多阶段过程，通常从癌前病变发展为恶性肿瘤。  Normal human cells: Are mortal in culture - Hayflick limit (50 +/- 10 cell divisions) Do not produce telomerase – cannot maintain telomeres. Undergo programmed cell death (apoptosis) Cancer cells: Are immortal in culture Produce telomerase（端粒末端转移酶） Resist apoptosis Normal cells respond to signals that: Stimulate cell growth and division (e.g. growth factors). Inhibit cell growth and division (e.g. contact inhibition). Initiate programmed cell death (apoptosis). As cells become malignant: They grow and divide uncontrollably. Lose contact inhibition. Become immortal. The apoptosis pathway breaks down. They express genes that stimulate production of blood vessels. They gain the ability to metastasize. Benign tumors – encapsulated growths - don’t invade and destroy adjacent surrounding tissue therefore not considered cancerous Malignant tumors – cancerous - invade and destroy adjacent surrounding tissue. Frequently metastasize i.e. slough off cells ? spread by lymphatic and blood to other tissues ? establish secondary malignant growth 1- Transformation. Process converting a normal cell into a cancer cell. If cancer cell evades destruction by immune system: 2- Tumor. Mass of abnormal cells within normal tissue. A tumor grows from a single cancer cell. Benign: remains at original site, most completely removed by surgery. Malign: invasive enough that impairs the function of one or more organs. People with malign tumors are said to have cancer. 3- Metastasis. Spread of cancer cells to locations away from original site. Clonal theory of cancer development Single cell genetically altered ? cell divis