我的一些关于肿瘤的观点
[i=s] 本帖最后由 饶冠华 于 2013-2-26 22:41 编辑 [/i]What is cancer? (by Guanhua Rao)
[b]Definition:[/b]
What is cancer? Cancer is defined as a solid or fluid-filled lesion that may be formed by an abnormal growth of cells which tend to proliferate in an uncontrolled way. Although cancer cells always accompany with different gene mutations or chromosome alterations, the only character that cancer cells shared in common is uncontrolled proliferation capability.
[b]Current situation and problems in cancer research:[/b]
Despite several decades of heavily funded research, cancer still kills millions of people every year. Although deaths from cancer have declined slightly since 2002, it is more likely depended on the earlier detection of cancers as well as lifestyle changes (such as quitting smoking), rather than dramatic improvements in treatments.
Why things are progressing so slowly in cancer research? What is the biggest problem about cancer research?
In my opinion, the so-called “reductionist” approach is the greatest barrier for us to realize the truth of cancer. As a matter of fact, the Mutation Theory (SMT), which qualified as ‘mainstream theory’ in cancer research, can’t resolve the problems of cancer. Just the same as Ana Soto & Carlos Sonnenschein once referred that the reductive thrust went as far down as needed to construct an explanation for cancer biology (1).
[b]To my understanding,[/b] the cancer is [ i] initiated by disrupting the normal cell-cell interactions. Regardless of intracellular process (such as oncogene activation or tumor suppressor gene inactivation), cancer is a cell-based disease. It means that a single cancer cell is the smallest unit of cancer. If we want know more truth about cancer, we should take a whole cancer cell as the object of study, rather than the oncogenes. [ii] Carcinogenesis does not require acquisition of a new function. Cancer cells are derived from normal cells, so most characters of cancer cells are the same as normal cells. [iii] The biggest problem caused by cancer is organ dysfunction, and cancer metastasis can lead to multiple system organ failure. [iv] Why does cancer metastasize? I think it is a random process that without any special purpose. However, if the microenvironment of tumor cells goes bad, they would like to escape from the unfavorable environment. For example, antiangiogenic agents could destroy the tumor vasculature, thereby depriving the tumor of oxygen and nutrients, and induced primary tumor reduction, however, they also increase lymphatic and distant metastasis of cancer (2).
[b]How to cure cancer?[/b]
As we all know, cancer metastasis is the killer for cancer patients. In my opinion, to cure cancer, first of all, reduce the chance of cancer metastasis. Secondary, rescue the organ’s functions. Thirdly, shrink the primary tumor. At last, enjoy the happy life.
1. Soto AM, Sonnenschein C. Emergentism as a default: cancer as a problem of tissue organization. Journal of biosciences. 2005;30:103-18.
2. Paez-Ribes M, Allen E, Hudock J, Takeda T, Okuyama H, Vinals F, et al. Antiangiogenic therapy elicits malignant progression of tumors to increased local invasion and distant metastasis. Cancer cell. 2009;15:220-31.
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个人之见，欢迎拍砖！ Good notions. It is the natural instinct to find a place to live for any living creatures. When you deprive their food, why they will not move? 不大同意上述定义， Wikipedia的定义如下：
[b]Cancer[/b] i/ˈkænsər/, known medically as a malignant neoplasm, is a broad group of various diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the body through the lymphatic system or bloodstream. Not all tumors are cancerous. Benign tumors do not grow uncontrollably, do not invade neighboring tissues, and do not spread throughout the body. There are over 200 different known cancers that afflict humans.[1]
Determining what causes cancer is complex. Many things are known to increase the risk of cancer, including tobacco use, certain infections, radiation, lack of physical activity, obesity, and environmental pollutants.[2] These can directly damage genes or combine with existing genetic faults within cells to cause the disease.[3] Approximately five to ten percent of cancers are entirely hereditary. 每个人都可以给肿瘤下个定义。以我看，楼主的定义并没有原则错误。Wikipedia的也并非完美，过于冗长。老狼，抱歉了。 [quote][size=2][color=#999999]sunsong7 发表于 2013-2-27 15:01[/color] [url=forum.php?mod=redirect&goto=findpost&pid=816417&ptid=65439][img]static/image/common/back.gif[/img][/url][/size]
不大同意上述定义， Wikipedia的定义如下：
Cancer i/ˈkænsər/, known medically as a mal ...[/quote]
对于一种还不怎么了解的东西，你觉得Wikipedia就能给一个准确的定义么？ [b]回复 [url=forum.php?mod=redirect&goto=findpost&pid=816579&ptid=65439][color=Olive]饶冠华[/color] 的帖子[/url][/b]
我比较倾向于接受将癌定义为“neoplasm”（赘生物、新生物）而不是简单的“ proliferation”（增生）。 同意sunsong7 的说法，我也比较倾向于将癌定义为“neoplasm”（赘生物、新生物）的说法。细胞变异（或突变）应该是新生物，赘生在正常组织上或当中。 [b]回复 [url=forum.php?mod=redirect&goto=findpost&pid=817061&ptid=65439][color=Olive]zb_ming[/color] 的帖子[/url][/b]
我个人观点并不觉得肿瘤细胞是一种新生物，看上去反而更像一种由正常细胞各种功能 杂乱组装而成的嵌合体。基本上每一种肿瘤细胞所具备的生物学功能和行为都能从不同的正常细胞中找到，肿瘤细胞并没有自创出任何新的东西。 "Why does cancer metastasize? I think it is a random process without any special purpose".
转移是肿瘤的一个重要的生物学行为。“行为”是远在分子机制之上，分子机制是为生物学行为服务的。如果没有目的的随机过程，分子机制也就是随机的了。那还研究分子机制干什么？
没有哪项生物学行为没有目的。当然，肿瘤转移既不是为了“支边”，也不是为了杀死其host，而是为了生存。生存是生物界的最基本、也是最高的原则，是硬道理！你用抗血管剂剥夺肿瘤细胞的食粮，它不转移，要等死吗？如果期待相反的结果，那不是你傻，就是它傻。 [b]回复 [url=forum.php?mod=redirect&goto=findpost&pid=817162&ptid=65439][color=Olive]饶冠华[/color] 的帖子[/url][/b]
何为“瘤”？其含义就是新生物。如你说，那人头上长了个瘤。你怎么知道？因为，正常没有。所以，是“新长出来的东西”。但瘤的实质是什么？你的理解很到位。