My mum has a lump that keeps bleeding when touched its painful and its not healing could this be cancer she is 78 but never smoked.

Where exactly is the lump? How long has she had it?

Smoking is not a reason for EVERY kind of cancer?

Has she seen a doctor about this? Please understand that we cannot diagnose over the internet.

No she hasn't seen the doctor as she was trying to treat it herself she only told me this morning bt I was under the impression that cancerous lumps weren't painful...

Again, where is the lump?

Many people, including some doctors believe that cancerous lumps are not painful. As a cancer survivor myself, I can tell you that some are.

Is the lump on/in her breast?

It could be a boil or a ingrown hair that became infected. It could be any number of things some serious and some not. Therefore...

It is so fool hardy to try to make a diagnosis over the internet and I might add very dangerous.

Your best medical advice is a doctor.