Kat -   I get asked that a lot. As far as we know, the only cancers that are contagious are these Tasmanian Devil facial cancers and this dog venereal cancer. There’s no need to worry that you can catch cancer from another person with cancer.

Chris -   Well having said that Kat, what about organ transplants because obviously, if there is a cancer that we don't know about lurking inside the donor organ, there’s a possibility you could transmit that, couldn’t you?

Kat -   There is a possibility and also, interestingly, in patients who have had organ transplants, they're often on immunosuppressive drugs to stop their immune system attacking the cancer, and in fact, this can lead to an increase in certain types of cancer in a patient.  But you shouldn’t be worried if one of your relatives is affected by cancer.  You can't catch it off them so that’s important to point out.

We posed this question to Margaret Stanley from the University of Cambridge:

HPV is transmitted from skin to skin.  So it’s very important to emphasize that you don't have to have full sexual intercourse, penetrative intercourse.  Foreplay, kissing is an easy way of transmitting.  Now, more men than women get cancer of the anus, the back passage.  Men get cancer of the head and neck and it looks as though more men than women get cancer there as well.  So yes, there are men who get HPV from women, women who get it from men, men get it from other men if they have sex with them, and it’s the same for women with women.

We posed this question to Elizabeth Murchison from the Wellcome Trust Sanger Institute...

Elizabeth -   Well cancer happens when genes called tumour suppressor genes and oncogenes are mutated and cause the cell to start dividing abnormally.  And this can happen when you get single point mutations in your DNA which mutate an oncogene or a tumour suppressor gene, but they can also occur when two genes can come together abnormally in a translocation and what this can often do is to drive a gene which is not normally active in a particular cell type up to an abnormal level of activity which can sometimes cause the cell to become cancerous.

Chris -   I get it.  So by the chromosomes rearranging themselves, the gene which would normally be off  in a cell can end up being put next to a gene which is normally on in that cell, so the cancer causing gene also gets turned on abnormally and makes the cell misbehave.

Elizabeth -   That type of thing, yes.