肿瘤、癌症、癌、肉瘤定义
肿瘤：机体在各种致瘤因素作用下，局部组织的细胞在基因水平上失掉了对其生长的正常调控，导致细胞的异常增生而形成的新生物。
癌症：泛指所有的恶性肿瘤，包括癌、肉瘤、白血病等。
癌：上皮来源的恶性肿瘤，如乳腺癌、支气管（肺）癌、胃癌、大肠癌等
肉瘤：间胚叶或结缔组织来源的恶性肿瘤，如骨肉瘤、淋巴肉瘤、纤维肉瘤、平滑肌肉瘤、血管肉瘤等
tumor、cancer、sarcoma、carcinoma定义
Tumor:tumor is an abnormal new mass of tissue that results when cells divide more than they should or don’t die when they should, which includes benign tumor and malignant tumor.
Cancer: malignant tumor is also called cancer, which is a term for diseases in which abnormal cells divide without control and invade nearby tissue and spread. And cancer includes carcinoma and sarcoma.
Carcinoma: carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs.
Sarcoma: sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
Leukemia: leukemia is a cancer that starts in blood-forming tissue, such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood.
Lymphoma and multiple myeloma:lymphoma and multiple myeloma are cancers that begin in the cells of the immune system.
原癌基因（proto-oncogene）
癌基因（oncogene）
抑癌基因（suppressive oncogene/tumor suppressor oncogene）
原癌基因：指存在于生物正常细胞基因组中的癌基因。正常情况下，存在于基因组中的原癌基因处于低表达或不表达状态，并发挥重要的生理功能。
癌基因：指体外引起细胞转化在体内诱发肿瘤的基因
抑癌基因：存在于正常细胞内可抑制细胞生长并具有潜在抑癌作用的基因。抑癌基因在控制细胞生长、增殖及分化过程中起着重要的负调节作用。
Cancer-critical genes are grouped into two broad classes, according to whether the cancer risk arises from too much activity of the gene product, or too little. Genes of the first class, in which a gain-of-function mutation can drive a cell toward cancer, are called proto-oncogene, their mutant, overactive or overexpressed forms are called oncogenes. Genes o the second class, in which a loss-of-function mutation can contribute to cancer, are called tumor suppressor genes. A third class, whose effects are more indirect, are those genes whose mutation results in genomic stability, a class we describe as DNA maintenance genes.
目前肿瘤的发病情况与趋势
癌症严重危害各国人民的健康与生命，而且癌症的发生率和死亡率逐渐上升。
《全球癌症统计2020年版》：乳腺癌发病率超过肺癌位于首位，而中国新发癌症病例人数、癌症死亡人数居全球第一。
《2015年中国癌症发病与死亡统计》：粗发病率和死亡率总和较1“4年同期数据略有上涨，一年新增病例近400万，肺癌占二成，与贫困、传染相关的癌症（如食管癌、胃癌、肝癌）负担减小，与西式生活方式相关癌症（如结直肠癌）患者增加。虽我国癌症5年生存率约为40.5%，与十年前相较提高了约10个百分点，但我国预后较好的肿瘤（如乳腺癌、甲状腺癌、前列腺癌等）5年生存率仍与欧美发达国家有差距。差距源于我国癌症患者的早诊早治率低、晚期病例临床诊治不规范。
