After I found one photo of a cancer cell online, I started finding a lot more.
Many of them were pictures of dividing cells joined by double cones, much like my constant A/V ratio cells (shown at right).
I wondered what might be dangerous about such cells, and it struck me immediately that cells like this, if they were long enough, could push past adjacent cells. Something like 40% of the human body consists of extracellular fluid that surrounds cells. So there’s probably plenty of space for cells to do this. By contrast, short cells (i.e. most normal cells) wouldn’t extend far enough, and if they could grow at all, they’d grow in situ. Cells with a long extension, if they were sufficiently energetic, could push their way past adjoining cells, first forming local tumours, and then metastasising into surrounding tissues. They’d be malignant cancer cells.
The longest cells (at the point of division) that I came across were HeLa cells. Below is a video of HeLa cells dividing over a 27 hour period ( 0.5 hours per snap). They divide almost explosively, moving far apart, and appear capable of easily pushing past adjoining cells.
Dividing cells with a short extension, that couldn’t escape in this way, would be confined to the locality where they first appeared. If they were energetic enough – pushy enough – they could form a local ‘benign’ tumour, which might if it grew large enough break through to surrounding tissues. Which suggests that cancer cells are rather more energetic – more pushy – than normal cells (shown in green). I’ve read occasionally that cancer tumours have a slightly higher temperature than surrounding tissue, which would be consistent with a higher energy consumption.
Another way that dividing cells might get past surrounding cells is if they’re small enough to slip between them. Such cells might not be particularly energetic or pushy. They might form a local tumour, and as the pressure in the tumour rose, small cells could be expelled into the local tissues.
Ordinary cells, which don’t seem to divide with cones connecting the two halves of the cells, would appear to have a short extension, and to be less energetic than cancer cells.
I was rather surprised that none of these characteristics of cancer cells received any attention in descriptions of the characteristics of cancer cells, which were described as uncontrolled proliferation, invasiveness, indefinite lifespan, loss of normal function, lack of adhesion. What they looked like didn’t seem to matter much, although it seemed to me that quite a lot could be deduced from their appearance, particularly while the cells were dividing. And in fact, many of the given characteristics of cancer cells seem to grow from their visible behaviour.
For if cancer cells can push past adjacent cells in the various ways that I have described, then they are inherently invasive, and also inherently likely to proliferate. And if a cancer cell escapes from the locality where it first appeared (for example, as a liver cell), the characteristics which had survival value there might not have any value elsewhere. If, by analogy, a Durham coal miner finds himself moved to Brighton, his mining skills may be of little value because there are no mines in Brighton (that I know of), and he’s likely to lose those skills as he learns new skills. Same with cells – a liver cell in a lung has the wrong skill set.
All of which inclines me to think that cancer cells may be a bit like vagrants. Normal cells – the cells in livers, kidneys, lungs, etc – would be solid citizens living in the suburbs and holding down steady jobs. But the cancer cell is a drifter (and perhaps a highwayman) who has lost his job and his home. If so, life is probably pretty hard for cancer cells, rummaging through dustbins for scraps of leftovers. Which may be why many of them don’t survive. And why those that do survive are often highly aggressive and energetic.
There’s quite likely a process of natural selection of cancer cells. As cancer cells multiply, some variants of them fare better than others, and these survive and have offspring which are even better adapted (as highwaymen, pirates, muggers, burglars, etc) to living on mean streets. So what starts out as a relatively innocuous form of cancer may gradually mutate into a successful variant whose numbers might occasionally explode (e.g. when they learn how to rob banks).
This is a variant of my nomads and settlers account of human society. The cellular settlers are the normal cells living in co-operative societies. The cancer cells are wandering nomads.