Talk:Cancer

Include some information about the definition of cacerogenesis, please.

Carcinogenesis

Carcinogenesis can be divided conceptually into four steps: tumor initiation, tumor promotion, malignant conversion, and tumor progression.

Mesothelioma

There should be an entry for Mesothelioma under "Forms of Cancer". There could be a link to Asbestos in the "Carcinogenesis" section of the Cancer article. There is no need for "Cancer of mesothelium: Mesothelioma - Information about cancer which results due to exposure to asbestos" in the "External links" section of the Cancer article; that link is already at the Mesothelioma article. JWSchmidt 13:45, 13 Apr 2004 (UTC)

prevention and screening

I thought the prostate screening was controversialErich 03:15, 30 Jun 2004 (UTC)

Throat cancer

As I write, the link above to throat cancer is red. Given all the coverage on cancer we have, this seems quite odd. Is there a better name to redirect it to - or is there a gap here? Pcb21| Pete 22:40, 28 Jul 2004 (UTC)

• Head and neck cancer - Nunh-huh 22:45, 28 Jul 2004 (UTC)

Sentence moved from cancer

"Also recent studies have found a very close relation betwen obesity and cancer, the main reason for that is that your lever can't process all the toxins of your body."

I agree this is a bit short. The relation between obesity and cancer has been proven in many tumours, but hepatic detoxicication is hardly an issue. Elevated concentrations of insulin and estrogens have been blamed, especially for breast cancer. The relation is not "very close". JFW | T@lk 16:08, 21 Oct 2004 (UTC)

There should be something in the article about obesity; "we estimate that overweight and obesity now account for one in seven of cancer deaths in men and one in five in women in the US" [1]. JWSchmidt 05:15, 24 Dec 2004 (UTC)

Cancer as a name

I was looking for information and the name "cancer": exactly why it is so called and when it was first given that name (what exactly about it looks like a crab?). Is the information here and did I miss it? If not could someone include it somewhere? Thanks. -R. fiend 00:16, 7 Nov 2004 (UTC)

It's the same in German (Krebs). It has to do with the shape of some malignant processes: they may be star-shaped or have tentacles (while benign tumors are often round). On mammography, malignant lesions suggestive of breast cancer indeed may resemble a crab. The etymology is doubtful; it is claimed to have originated in the 17th century[2], but some put it to Galen[3]. Alternatively, it has nothing to do with crab but is due to the Middle-English canker (hardening)[4] - which is also a name for the typical lesions of syphillis (chancre in French). JFW | T@lk 00:47, 7 Nov 2004 (UTC)

Cool, thanks. Should this be added to the article in some way? -R. fiend 06:18, 7 Nov 2004 (UTC)

de:Krankheit als Metapher.--Nerd 12:10, 7 Nov 2004 (UTC)

I would certainly write something about the etymology. The conclusion is of course that we don't know. JFW | T@lk 12:45, 7 Nov 2004 (UTC)

The word "cancer" itself comes from the Latin word for crab (just like the constellation), and is so called on account of early physicians noticing the similarity in the shape of a tumor to a crab. This shape, as I understand it, is on account of angiogenesis, the growth of outward-sprawling blood vessels to feed the tumor, looking like the legs of a crab. That’s my understanding. Martschink

what does the root 'carcin' mean? i see it in 'carcinogenic' as well as 'carcinization' meaning "becoming a crab" is this a related word for crab that somehow managed to affix itself to both meanings of 'cancer' ?

My dictionary says that carcinogen comes from the Greek word karkinos which literally means "crab." —Brim 03:30, Mar 9, 2005 (UTC)

Graph

I'm not at all happy about the graph showing the connection between smoking and lung cancer. Where does it come from? Was it plotted by a Wikipedian? If so, where did that person get their data from? No sources are cited, which leads me to suspect that this graph has just been fabricated. If so, that's a terrible deception. I don't doubt the link between smoking and cancer, but the lines on the graph look conveniently and improbably similar. Somebody please clarify. Palefire 22:24, Dec 8, 2004 (UTC)

I was not the Wikipedian who uploaded the graph, but a simple Google search revealed that the graph is published on the NIH website. No references were given on that particular web page, so I'm not sure how the graph was generated, but I would believe that the data are valid if they're from the NIH. — Brim 01:52, Jan 22, 2005 (UTC)

Deleted sentence fragment

Original paragraph:

<<Mutations can also be inherited. Inheriting certain mutations in the BRCA1 gene renders a woman much more likely to develop breast cancer., chronic inflammation from any cause.>>

Deleted fragment: <<, chronic inflammation from any cause.>> ---Rednblu | Talk 10:21, 12 Dec 2004 (UTC)

When Healing Becomes a Crime article

192.80.65.234 [5] and 63.164.145.198 [6] — please stop adding the section Articles containing:

• When Healing Becomes a Crime from Tikkun

The article When Healing Becomes a Crime: The Surprising Facts Behind 'Unproven' Cancer Therapies by Kenny Ausubel is not an important reference in the encyclopedic article about cancer. Rafał Pocztarski 02:28, 22 Dec 2004 (UTC)

Why should this be NOT added?? Or maybe it should be put in it's own section or referenced to at least in some way. As a cancer patient, I am painfully aware of the politics at play because of all the money at stake. I live in the DC suburbs, and PERSONALLY heard a PhD. Pharmocologist that had his Pharmacy nead the HQ of NIH say, "NIH is OWNED by the drug companies! I know many people that work there and that is what they would tell you, if it would not cause them to loose their jobs."

Your argument suffers from the logical fallacy of 'Appeal to Authority' and even in that it fails. You cite some person that you do not name and attribute a statement to them that is purely opinion. If you think the article should be included, say so (you do), but make a better argument than the one you made. I too am a cancer patient (Hodgkins, stage 3B) and I believe it's very important that the information in this article either be verified as factual or clearly labled as unproven.

Why not have a section devoted to all the alternative medicine thearopies that have been advanced by different people over the years. It need not endorse them,nor condem them. Certianly the case of of Harry Hoxsey is one of public record, after all it is said that there were court cases, etc. so why can't it be documented as part of the history of the search for a cancer cure?

I wandered "in here" looking for information on the metabolism of cancer cells. I have found a reference to anerobic glycolysis in cancer cells but cannot find additional supporting information in the form of refered journal articles. HELP! Please. Thank you.

Jfdwolff reversion of 68.108.100.105 link addition

Jfdwolff,

Was your reversion of the link addition by the anonymous 68... due to the low value of adding a link to a link farm page?

Courtland {2005-01-27 USA ~8PM EST}

GENERAL QUESTION: What is a "benign" tumor?

What, exactly, is a "benign" tumor? Sure, it's not dangerous and all that, but is it going through uncontrolled cell reproduction or not? Do the cells of a benign tumor go through apoptosis or not? (And for that matter, what do we mean when we say "tumor"? Is it just a fancy word for "ugly clump of cells"?) Do the cells in a benign tumor function properly? Does anyone know where I can find out more about benign tumors beyond the uninformative contrast with their malignant counterparts? And while we're on the subject, there's some recent news about carrots affecting somthing called "pre-cancerous tumors." (See e.g., http://www.sciam.com/article.cfm?chanID=sa003&articleID=000948D4-3498-1209-B49883414B7F0000) Does anyone know what a "pre-cancerous" tumor is? Is that like a pre-pregnant girl, a pre-shut door, or a pre-caught fish? The National Cancer Institute gives the following ho-hum definition: "A term used to describe a condition that may (or is likely to) become cancer. Also called premalignant." Not so helpful, really. And why does it seem that so many cancer studies (like the above-mentioned carrot study) are premised on correlation rather than causation? Martschink

A benign tumor is certainly a neoplasm, but it does not invade other tissues. It still arises from uncontrolled mitosis. Premalignant are benign tumors that are statistically likely to degenerate. The word precancerous is rubbishy; don't use it. JFW | T@lk 22:41, 9 Feb 2005 (UTC)

Benign tumors lack the ability to invade other tissues and lack the ability to metastasize. However, being benign does not mean they're not potentially dangerous. A decent definition for a tumor is "a clump of cells that grow uncontrollably." So, benign tumors still grow uncontrollably. That answers your question "Do cells in a benign tumor function properly?" No, they do not, since they grow uncontrollably. They lack the function that normal cells have which is to be able to recognize their bounds and to stop growing when they become crowded. "Pre-cancerous tumors" are tumors that are pre-invasive — they haven't yet invaded beyond the basement membrane of the epithelium. Since they haven't invaded beyond the epithelium, they therefore lack the ability to metastasize. You might be tempted to call these tumors benign, but in practice that is not usually done. The obvious conclusion that you can come up with when something is called "pre-cancerous" is that someday it will become cancerous. That is our basic understanding of the development of cancer, that a few mutations in the genes which regulate cellular growth lead to tumors that grow but lack the ability to invade (pre-cancerous), then more mutations take place which give them the ability to invade tissue (malignant) but as of yet haven't metastasized, then additional mutations give them metastatic potential and they invade into the lymphatic system or into capillaries. It's a rather simplistic view (especially considering the hundreds upon hundreds of genes and the interplay of multiple cellular signalling pathways) but it does a good job of describing what happens. Your last question is the most difficult one to answer. Basically, studies of causation are inherently difficult because one can never see inside the "black box" of a system; we can only observe inputs (conditions, treatments) and outputs (results: dying from cancer or a tumor shrinking). In most scientific experiments, conditions are highly controlled. For example, for a chemical reaction reaction where chemical A is combined with chemical B to produce chemical C, you can vary the concentrations of both chemical A and chemical B to see the effect on the kinetics of the reaction. Since everything else is controlled for, you can conclude that "increasing the concentration of A leads to an increase in the reaction rate". This doesn't necessarily prove causation, but since all other variables are controlled for, you can conclude that it's the only reasonable explanation. In humans, however, we obviously can't do experiments like that. All we can do is get a bunch of people (example: people with lung cancer), try an intervention (a new cancer drug), and look for a specified results (tumor shrinkage, time until death). However if people who get Drug X live longer than those who don't get the drug, you can't really conclude that Drug X caused them to live longer since it's not a controlled experiment. Your groups of people are not exactly the same. They're NEVER exactly the same. One group or the other will have older patients, they might metabolize the drug differently, they have different stages of disease and different tumor types (not all lung cancers behave the same way), etc. There are infinitely many variables. Even after all the statistical tests we do to eliminate the effects of random differences between groups causing differences in outcome, all we can safely conclude at the end is "Yes, Drug X is associated with a better outcome" or "No, Drug X is not associated with a better outcome." We can't say Drug X caused the outcome to happen. — Brim 05:44, Feb 10, 2005 (UTC)

Thanks for the answers, Brim. I'd like to rephrase one question, the one about whether cells of a benign tumor function properly. Other than their growth problem, do the cells do the stuff they're supposed to do? That is, do the cells of a benign tumor in the liver do the work of non-cancerous, non-malignant, non-tumorish, plain-vanilla liver cells? Martschink 07:57, 11 Feb 2005 (UTC)

That's a tough question to answer. I'm definitely not the most authoratative person on this subject, but I think I can give you a rough answer. It depends on the type of tumor. It also depends on how you define function—are you looking only at gross functional abnormalities or biochemical changes? Most common malignancies are of epithelial tissue, which have no real function other than to serve as a barrier. A good example of a tumor that can lose its function is a pituitary adenoma. The normal function of cells of the anterior pituitary gland is to produce one of the several pituitary hormones. Adenomas of the pituitary are usually classified as "functional" or "non-functional". The functional tumors continue to manufacture hormone and actually lead to an excess of hormone, causing symptoms. However the non-functional tumors don't produce hormones. So this is an example of how a tumor can continue to function "normally" or stop its normal function. By the way, while a pituitary adenoma is a benign tumor, this applies to malignant cancers as well. For example, in malignant germ cell tumors of the testis or ovary, the cancerous cells continue to secrete hormones like B-HCG. However, as I alluded to earlier, there may still be biochemical derangements within the cell, so even cells that continue to have part of their normal function have other abnormalities. Oncogenesis in a complicated process with several changes occurring in the cell. We know that most tumors have defective DNA repair processes, which in part is responsible for how they turned into neoplasia in the first place. I hope this answers the main part of your question. It's a fairly complicated topic to be able to talk about if a cell is "normal" or not. Someone with more of a cell biology background might be able to give you a more in-depth answer. — Brim 19:41, Feb 11, 2005 (UTC)

I wanted to clarify something in the example of pituitary adenomas. While functional adenomas produce pituitary hormones like normal pituitary cells, they are not really normal since the process is not properly regulated. Adenomas will continue to produce pituitary hormone even when the hypothalamic signal is inhibited. — Brim 20:28, Feb 11, 2005 (UTC)

Wording of the first paragraph

The first paragraph begins "Cancer is a group of diseases". Is this completely true? Would you say "melanoma is a member of cancer" or "melanoma is an example from cancer". No, you always say "melanoma is a cancer" or "melanoma is an example from the cancer family". The reason I post this here rather than boldly editing is that I think I'm wrong. So, what do people think? Anyhow, it seems to me that if you introduce it as a group of diseases, to say that that group is caused by DNA damage (later in the paragraph) is to slightly miss the point. Its the members that are caused by this. Does anyone think that this would make the paragraph easier to read if changed? --Mike C | talk 08:00, 27 Apr 2005 (UTC)

I think it is prudent to refer to the various cancers as different diseases, together forming the group of malignancies. If cancer was one disease, how come skin cancer is curable and mesothelioma patients all die? The intro should firmly unseat the public perception that all cancers are similar. They are not; they only share their pathogenesis, and even in that respect they differ wildly (e.g. hematological malignancy is a different kettle of fish altogether). JFW | T@lk 20:42, 27 Apr 2005 (UTC)

PS I would refer to melanoma as a "form of cancer" in the same way I would refer to angina as a form of cardiovascular disease.

I haven't made myself very clear, sorry. Of course the different cancers are different diseases. My question is one of semantics. It is made very clear by your PS. If we take as example of a group: "a flock of birds" where a parrot is a member, we would never say "a parrot is a form of a flock of birds". This leads me to question whether cancer is not "a group of diseases", but rather a noun referring to any member of the group of cancers (hmm kinda cyclical sounding, but it is the group that is dirivative and the members that are defined). Do you see what I'm getting at? Its a rather silly point and I'm still not sure it warrants changing. --Mike C | talk 01:39, 28 Apr 2005 (UTC)

Your new form sounds odd. Cancer is a group, and the various forms (e.g. oesophageal carcinoma, soft-tissue sarcoma) are its members. You can refer to those diseases as a cancer like you would refer to myocardial infarction as a cardiovascular disease. JFW | T@lk 06:02, 28 Apr 2005 (UTC)

I agree the alternative form sounds odd. But I'm now convinced that the current version doesn't quite make grammatical sense. You wouldn't, if writing an article "tree", start off "Tree is a group of tall perenial woody plants". If you wanted to phrase it like this, you would have to say "The trees form/are a group of...". Do you see what I'm getting at? I'll concede to you, though, if no-one else supports me. I'm open to the fact that I'm just plain wrong. I'd accept instantly if you can give an example where "cancer", in that exact wording, is used a group. But, in your above case, you're reffering to a cancer, a member of that group. Most groups I know have an article in front, either "a football team" or "The Star Alliance". However, I can't see how an article can be put in front of "cancer" to make it a group. I'm really confused, now. Please help tease this out. --Mike C | talk 13:03, 28 Apr 2005 (UTC)

To my (non-native speaker) ears the present form is not wrong. Perhaps you feel the word "group" should be associated with a plural term, but some groups do go by their singular. Perhaps the village pump is a nice place to discuss this. I will settle for "cancer refers to a group of diseases", which should resolve the problem. JFW | T@lk 20:51, 28 Apr 2005 (UTC)

I think you're right. The present form sounds fine. Lets leave it for now. --Mike C | talk 11:54, 29 Apr 2005 (UTC)

Geopathic Stress as a cancer risk factor?

I'm quite doubtful that geopathic stress is accepted in mainstream (non-alternative/complementary) medicine as a component cause of carcinogenesis. Perhaps someone could correct me / correct the article? Thanks.

--Guohao 14:26, 2 May 2005 (UTC)

It's raving pseudoscience. JFW | T@lk 19:21, 2 May 2005 (UTC)

Blood Vessel Supply Within Tumors

Something that isn't perfectly apparent to me is why the body supplies tumors with a full supply of blood vessels, for keeping the tumor alive, as it were. One can easily understand how a mutation can cause a single group of cells to reproduce in an unhealthy manner, but what is it that causes the body to grow a complete circulatory system for the tumor? And, along these lines, does the body also supply the tumor with nerves? And lymphatics?--McDogm 15:52, 6 May 2005 (UTC)

A tumour requests the new blood vessels using the same methods as any non-cancerous bodily tissue. A protein called vascular endothelial growth factor VEGF is secreted by most cells which are not being supplied with enough oxygen. there is a clever and not-fully-understood control mechanism involving mRNA stability and a gene called HIF-1 that stimulates VEGF gene transcription. VEGF stimulates the growth of nearby blood vessels into the tissue.

This process is known as angiogenesis and there is some useful information on the relevant page. A fast growing tumour is going to use up a lot of oxygen, so VEGF would be secreted anyway. However, in cancers, the genes coding for chemicals such as VEGF are permanently switched on, as these mutants are favoured by the "clonal selection" process described in the cancer article. Thus, very large amounts of these angiogenins are produced, and blood vessels form. Of course the body wouldn't "want" to supply cancers, but it cannot distinguish the tumour from a healthy tissue short on O2. Angiogenesis is a critical process in the generation of malignancy. Without it, fast growth is not possible and critically, metastasis will not occur. For these reasons, it is a key target of anti-cancer research.

Nerve cells are very reluctant to grow in adults (unfortunately for spinal injury victims) and their growth would not be beneficial to the tumour cells, so would not be selected for. Lymph, again, is not very important to the tumour, as it is there to deal with the osmotic physiology of the entire organism and its lack would not prevent growth. See teratoma for some tumours in which strange cell differenciation (including nerve cell and presumably lymph tissue) occurs, although for completely different reasons. I hope this has answered your question. If not, explain your concerns and I'll try and work it through with you. I'll also put some of this onto the angiogenesis page. --Mike C | talk 22:11, 6 May 2005 (UTC)

Thanks; I have a sneaking amateurish suspicion that lymphatics and their development may be some kind of an adjunct of angiogenesis but since we are talking about tumors here that might not make sense from a canonical mRNA science standpoint. I'm just a solid amateur but I like lymphatics and I am sure I remember that lymphatics are essential for capillary function. A tumor without lymphatics would be undrainable as a mass of tissue. I knew that nerve doesn't really grow very much in the body after a very early stage. In terms of bedside manner and DRG days it seems to me that for the cancer patient it would be good for the doctor to be able to say something helpful about oncoangiogenesis to the patient and their family. Is that word good? Personally I think the oncoangiogenesis, as it were, is a very vulnerable part of the tumor in terms of effecting cures. It makes a lot sense to me that it is a critical topic of study. On a mundane basis oncoangiogenesis goes culturally to the paradigm of economics, in which resources are allocated quite carefullly. It really makes sense to the patient, in other words, to gain leverage over the disease through understanding the negative cultural aspects of oncoangiogenesis as compared to ordinary personal relations and current events. In other words, there is usually a quid pro quo for services rendered, or in even more colloquial terms, one has to pay the (utility) bills. That's just common sense and it is really easy to explain in lamen's terms.

The mRNA mechanisms et al are of course the core of continuing study of the cancer problem.--McDogm 15:49, 7 May 2005 (UTC)--McDogm 19:44, 7 May 2005 (UTC)

Oncoangiogenesis is not a very current term. There is also very little point in discussing it with cancer patients - all treatments in this respect are experimental (although it is one of the underpinnings of radiation therapy). I must say that the role of lymphatic drainage is not crucial to tumorigenesis, as lymphatics usually bear a close relation to the arterial supply of any tissue and probably form together with the blood vessels.

Tumors have no nerve supply apart from the autonomous nervous system branches that come with the blood vessels. JFW | T@lk 22:26, 7 May 2005 (UTC)

What are the genetics of tumorangiogenesis and tumorlymphiogenesis? As I understand the reading, tumors cannot grow more than 3 cubic millimeters w/o angiogenesis. What exactly does angiogenesis, or more descriptively, capillariogenesis, have to do with whether a tumor is malignant or benign, at the nuts and bolts level?--McDogm 16:20, 13 May 2005 (UTC)

Is the commencement of angiogenesis the moment of change from benign to malignant? Of course, if there is no angiogenesis, the tumor will not generally grow bigger than 3 cubic millimeters, so angiogenesis is important. But is it the central factor in malignancy? Is angiogenesis the door to curing cancer?--McDogm 13:24, 14 May 2005 (UTC)

Hmmm. Expression of collagenases and MMPs is more likely the defining factor - metastasis can occur when the cells can invade other tissues. I suspect proangiogenetic mutations probably occur earlier rather than later. Inhibiting angiogenesis as a cancer cure is the premise of the Folkman hypothesis. Malignant cells will develop, but will be starved of nutrients as they cannot command adequate angiogenesis. Some antiangiogenic drugs (including thalidomide) are undergoing trials, so I suppose the experimental evidence will tell us if antiangiogenetic therapy will cure cancer. JFW | T@lk 19:31, 22 May 2005 (UTC)

Acrylamide

I was wondering what other health professionals around the globe believe about Acrylamide, whether it is Carcinogenic or not.

In vitro it appears to be a carcinogen, but cancer indicence due to the consumption of acrylamide-rich foods is not as shocking as has been suggested. JFW | T@lk 19:31, 22 May 2005 (UTC)

Frequency of different cancers

Please can we have some information of the relative frequency of different types of cancer. Even a simple pie chart would be useful.

Hmm, these are different in each country. Are you asking for worldwide statistics? There may be obtained from the WHO. If you provide an URL, I'll gladly make an OOo pie chart! JFW | T@lk 12:48, 24 May 2005 (UTC)

Article Length

This article is getting a little on the long side. Does anyone have any ideas about shortening it? --Mike C | talk 11:00, 28 May 2005 (UTC)

I think this is just about right. You can't make such a major topic much shorter than this. You may want to find redundancies, and some sections may be shortened with more information added to subarticles, but on the whole I don't think you can slim this down any more. JFW | T@lk 06:41, 29 May 2005 (UTC)

Featured article?

This article needs to become a featured article. With all those nice graphics and most subpages written it should be worked on to become a WP:FA. JFW | T@lk 05:25, 6 Jun 2005 (UTC)

I agree. I made a few changes to improve things, and I see you did too. Here's some things that are still bothering me. We should fix some of this before starting it onto the featured article road.:

1. The origins of cancer section. It is incomplete, I don't know if it should be expanded or replaced or deleted.
2. "Adult cancers are usually formed in epithelial tissues" is followed by a list that includes many non-epithelial cancers
3. The list following "Childhood cancers include, from most frequently occurring to least" includes a mixture of cell types (germ cells, epithelial) and cancers (neuroblastoma)
4. the immunotherapy section gives me problems. Herceptin is not using the patient's immune system against the cancer, it uses a mouse's immune system. I think this section should be lumped into chemotherapy unless it goes into a discussion of cancer vaccines, which are still pie-in-the-sky, except for the hepatitis B virus vaccine.
5. "Contrary to expectation, randomized trials found no benefit" begins a string of confusing statistics about diet and cancer. I believe the basics are: diet has some affect, smoking tobacco much more of an effect. Specifics about diet are not yet well established.
6. the statement about cancer being the leading cause of death is incomplete, in the united states, at least, it is only true for people under the age of 85. Note 2, the reference, is now pointing to a dead page.
7. the Cancer research section is weak. Just a grab bag full of things.

Jpbrody 22:17, 7 Jun 2005 (UTC)