12

What are the differences between cancer and tumour? I mean is it in the DNA or shape or something else... And how can a benign tumour turn into a malignant tumour? The body has a lot of tumours all the time, however not all of them become cancerous, why is this so?

So my main question is: What is so special about cancer cells that they can get out of control unlike an ordinary benign tumour?

Anne
  • 1,624
  • 12
  • 18
Malic Of Sdom
  • 325
  • 2
  • 7
  • 1
    please accept an answer. It is considered impolite when the question has been answered to the fullest and the OP (original poster) has not accepted an answer. It means that the OP is expecting something more. So if you feel that the question has been answered, then please accept the answer which has suited you. – One Face Jan 29 '15 at 14:01
  • What is the difference between "a car" and a "Volvo XC60"? What is difference between "disease" and "sarcoidosis"? What is the difference between "planet" and "Earth"? – Ilan Aug 08 '15 at 06:16

2 Answers2

19

A tumour is simply a space-occupying lesion (something that should not be there, that is; a "lump") caused by abnormal cell replication.

(In medicine, the word "tumour" literally means "swelling", and can sometimes refer to that instead, but that's a different story).

Cancer is a disease in which cell replication is totally out of control. What causes cancer is damage to the genes (DNA) which normally stop cell replication when it needs to be stopped.

There's no such thing as an "ordinary tumour"; all tumours are abnormal. However, what makes a benign (harmless) tumour different from a cancerous tumour is that there is still some mechanisms stopping the cells inside the tumour from replicating; they are doing it more than they should, but they are not totally out of control. When those last mechanisms are broken too, the tumour is cancerous.

(This is a simplified explanation; the actual explanation is a semester-long university course. It's mostly accurate for the layman, though)

Watercleave
  • 486
  • 2
  • 11
  • Thanks! and where can I get the "actual explanation"? can you give me an outer source for that?(book/site etc) – Malic Of Sdom Jan 24 '15 at 17:45
  • 1
    Wikipedia is always a good start; the article on cancer has a "Further Reading" section down near the bottom. – Watercleave Jan 24 '15 at 17:49
  • Uterine smooth muscle tumors other than the ordinary leiomyomas and leiomyosarcomas: a review of selected variants with emphasis on recent advances and unusual morphology that may cause concern for malignancy. ') Just nit picking here, but I do believe many kinds of "tumors" are so common that they deserve the appellation "ordinary". Subcutaneous lipomas, for instance. – anongoodnurse Jan 24 '15 at 21:22
  • 2
    Hallmarks of Cancer: The Next Generation is a review article that'll provide a great understanding, sorry for no link, on my phone. – CKM Jan 24 '15 at 22:44
  • 1
    @Kendall here is the link to the 2011 Cell article by the same name. I could download the PDF at home, so I believe it's open-access. – MattDMo Jan 24 '15 at 23:36
  • @anongoodnurse You make a good point; I think it depends on your definition of "ordinary". All tumours are out-of-the-ordinary in one sense because they come about due to cellular dysfunction - cells doing what they would not ordinarily do. In another sense, though, I suppose some "ordinary" tumours do exist. – Watercleave Jan 25 '15 at 08:14
  • @anongoodnurse I am confused about the title, does it imply that leiomyosarcomas are also ordinary? I agree that leiomyomas are ordinary as are lipomas – One Face Jan 25 '15 at 09:50
1

Tl;dr answer, tumors are abnormal growth (or swelling, thanks to Malic for pointing out) of any kind. The kinds of tumors are benign and malignant.

Benign tumors are usually slow growing and harmless. Example would be a lipoma.

Malignant tumors are otherwise called cancers. They generally have a bad prognosis. Very few cancers are curable.

Swelling over an injury (which is also called tumor) is due to local transudation (shift of plasma from capillaries). This is temporary and usually goes down one the injury heals.

One Face
  • 3,082
  • 1
  • 22
  • 38
  • All of the tumors are abnormal? I heard that if part of the body get hurt, the body does a tumor on purpose to fix the part that get hurt, is it true? and there is a lot of small tumors in the body at a given moment? – Malic Of Sdom Jan 25 '15 at 09:32
  • 1
    When a part of body swells, it is also called tumor. Thanks for pointing out! @MalicOfSdom. But that swelling is also considered pathological. As it is a deviation from physiology – One Face Jan 25 '15 at 09:35
  • haa! so every time a part of the body swells it is tumor...scary! and does a benign tumor can turn to a malignant tumor? – Malic Of Sdom Jan 25 '15 at 09:42
  • Yes, it can occur. Some benign tumors are more prone to malignant change while some practically never do – One Face Jan 25 '15 at 09:45
  • In general, though tumor can denote any swelling regardless of the presence of any growth, practically speaking, doctors rarely use the term tumor to denote an edematous swelling. So for practical purposes, the word tumor means abnormal growth – One Face Jan 25 '15 at 09:46
  • ha ok, and when I get hurt for example in the bone, the swell on it is benign tumor? what is the chance that it will convert to malignant tumor? – Malic Of Sdom Jan 25 '15 at 10:33
  • @MalicOfSdom Tumors due to swelling in response to injury will never turn malignant. Only benign tumors due to abnormal growth has the potential to turn malignant – One Face Jan 25 '15 at 10:35
  • and how this turn from benign to malignant obtained? is it in the genome of the tumor or something else...? – Malic Of Sdom Jan 25 '15 at 12:15
  • @MalicOfSdom you should post this as a new question. There are many theories in that. Searching in wiki will be of great help too. – One Face Jan 25 '15 at 12:20
  • one more thing: malignant tumor always strarts from a benign tumor? – Malic Of Sdom Jan 25 '15 at 12:23
  • Not always, can start from normal cells too – One Face Jan 25 '15 at 12:25
  • @CRags - you've given a number of incorrect answers here. Curable cancers are not few and far between. Malignant tumors are not always deadly (see, for example, basal cell carcinomas). You should try to stay within provable statements when answering questions. – anongoodnurse Jan 29 '15 at 04:11
  • 1
    @CRags - no, I don't agree; if I did, I would not have left that comment. I define "cure" like any normal person: it's gone and will never bother you again. It is possible, and it is done every day, to declare a cancer patient cured. Childhood leukemia is now a largely curable disease; others include some lymphomas, cervical cancer, and others if caught early. Clearly there are some that, regardless the initial response, can still come back. I'm just saying, don't make claims which are untrue. BCC is a malignant cancer with a very good prognosis, if not even excellent. – anongoodnurse Jan 29 '15 at 16:20
  • 1
    Yes, I got it. I will be more careful @anongoodnurse Thanks for helping me answer better – One Face Jan 29 '15 at 16:33