If anyone has been to the Beatson up at Gartnavel hospital, then they might have spotted that one of the buildings is the Tom Wheldon building. Now, this was named after my old boss. He was a great wee guy, was Tom. In one sense, he was the epitome of an absent-minded professor. He was often seen wandering about the department as if in a daze (and on one memorable occasion he managed to miss the fact that a service hatch was open in the floor, stepped over the warning sign and plunged down the hole. Only his elbows stopped him ending up in the sewers). But he was also a sharp and funny guy, and it is one of his quips that gave me the subject for this post.
Tom was diagnosed with colon cancer back in 1999. At around the same time, one of my colleagues became pregnant and when Tom found out, his reaction was to comment, “Well, it looks like we both have something growing inside us, but nobody is knitting bootees for mine!”
He passed away back in 2000 and is still sadly missed. RIP Prof Tom Wheldon.
But it was reminiscing about this anecdote which got me thinking about how cancer grows and develops. Now, a lot of people diagnosed with cancer treat it as though it was something separate from themselves. As if it was some strange, alien….thing that had invaded them. But it isn’t. As I mentioned before in No Cure For Cancer…?, cancer doesn’t come from outside, it comes from inside. It is a collection of your own cells that have gone wrong.
Normally, the way that the cells of your body grow and divide are strictly controlled. We all start off as a single cell – a fertilised egg. That single cell will start to divide, first into two cells, which then grow and divide into four cells, which then grow and divide into eight cells….etc, etc. As they grow and divide, different areas of the enlarging cell mass will start to develop differently – into limbs, lungs, kidneys, etc…until 9 months later….POP! Out comes a baby. Even then, the growth & division of cells continues as the baby becomes a toddler, then a child, then an adolescent. And all the time, cell growth and division is occurring as the child grows. That growth and division is controlled by the release of various signals inside the cells themselves. There are, roughly speaking two sets of signals**. The first set make the cells divide – let’s call them Go! signals. The second set make the cells stop dividing – I’ll call them Stop! signals.
(**There is also a third set of signals – the ones which make the cells specialise into heart cells, lung cell etc. These could be described as Change! signals, but I won’t discuss them here – let’s just stick with Stop! and Go! for the time being, M’kay?)
Eventually, of course, the child becomes an adult, and stops growing. But that doesn’t mean that there are no more Go! signals being made. On the contrary, they are happening all the time. Most people have heard the (probably inaccurate) statistic that house dust is mainly old skin. And, it is true that dead skin cells are flaking off all the time – about 30,000 a day in fact. But you don’t eventually run out of skin, do you? You don’t end up having to cart your internal organs around in a wheelbarrow, right? Well, that’s because the skin cells that flake off are replaced by new skin cells. And how are the new cells made? Easy. The basal layers of your skin make a short burst of Go! signals, which then make the base-layer cells multiply, in order to replace the lost, dead cells. Once all the lost, dead cells are replaced, the basal layer makes some Stop! signals and the cell division ceases.
And this doesn’t just happen to your skin. The same process also happens inside your body. Old cells die and are either excreted or recycled. And they are replaced by newly made cells. So you can think of your insides as a large, complicated, multi-layered chorus of different signals going off at different times in different organs, “Go! Stop!… Go! Stop!… Go! Stop!… Go! Stop!”
But then we come to cancer. What cancer is, basically, is an imbalance of Go! and Stop! signals. A tumour develops because one cell, or maybe a small collection of cells, have too many Go! signals, and not enough Stop! signals. This can happen for a variety of reasons. Maybe they make far too many Go! signals. Maybe they stop making, or stop recognising the Stop! signals. Often all of these happen together. But, whichever way round, the upshot is the same. The only signals that the cells end up hearing are the ones saying, “Go! Go! Go! GO! GO! GO!! GO!!!” And the cells respond by growing and dividing. And dividing. And dividing. And dividing…
And as this continues, you end up with a large, ever-growing mass of cells. Which is what we call a tumour. Now, the rate at which the tumour grows depends on the strength of the Go! signals. If they are relatively weak, then the cells divide infrequently, therefore the tumour grows slowly. But, if the Go! signals are relatively strong, then the cells divide frequently, and therefore the tumour grows quickly.
Also, if the tumour stays together as one, single lump, then that is what we call a benign tumour. However, sometimes (too often, unfortunately), the tumour doesn’t stay together. Instead, bits of it break away and start floating around the blood system. And this is bad, because these bits are still capable of growing & dividing. So, they will travel around the bloodstream until they find a nice little spot to settle down…maybe in the liver, maybe in the lungs, maybe in the bone marrow…and then they will start to divide. And a secondary tumour forms. This type of disease is what we call malignant. Again, whether a tumour is benign or malignant will depend on what type of Go! signals are being made. Some will encourage the dividing tumour mass to stick together, while others will encourage bits to break off and form secondaries.
Now often, but not always, these two factors can be connected. So, slow-growing tumours are often benign, fast-growing tumours are often malignant. But, as is always the case in cancer research, there are no simple answers, so you can also get slow-growing malignant or fast-growing benign diseases. It all depends on the signals being made within individual tumours, within individual patients. And, also, the situation is not static. So, a slow-growing tumour can start making different Go! signals and start to grow more quickly, and a benign tumour can also start making different Go! signals and become malignant. And sometimes, very VERY rarely, the tumour switches off the Go! signals altogether and starts making Stop! signals instead. This is what we call a Spontaneous Regression, such as was seen in the case I discussed in Venusian Blancmanche Therapy. How do these happen? And can we make it happen more often?
Very good questions – I wish I had the answers. But that is what a lot of cancer research is doing. Looking at the large (actually, vast) number of different Go! and Stop! signals, to try and … er … stop Go!ing and start Stop!ing.
AG McCluskey (2015). No Bootees Zongo’s Cancer Diaries