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From: "Lizzie Love" <>
Subject: Re: [trivvies] smoking
Date: Fri, 14 Mar 2003 14:38:17 -0000
References: <00d901c2e4c3$37e67140$0100007f@qjtmb>


Katy wrote:
> emma had a rare cancer ,this is a weird one,apparently she was born with a
> piece of lung tissue in her abdomen and it was this that turned cancerous
> and eventually spread to liver etc

Dr Peter will correct me if I'm wrong, but I think this must be another
developmental hiccup, like the one that caused the cyst in Neil's brain. It
does sound really weird doesn't it?

During the first few weeks after conception the cells of the embryo start to
differentiate in preparation for making different sorts of tissue. The
embryo becomes a three-layered disc ... ectoderm (inside bits ... mostly the
linings of your innards) ... mesoderm(middle bits ... mostly muscle, bone
etc) ... and endoderm (outside bits ... the outside of your skin ... and all
nervous tissue, which isn't as odd as it sounds) ... At this point it
executes a piece of advanced origami so neat, so simple and so miraculous
that I'm awestruck every time I think about it.

First it makes as if to roll itself up with the skinside inside, but just
does a quick nip and tuck to form a channel down the middle (where the brain
and spinal column will be ... and then it rolls up in the other direction
leaving the skinside outside and the linings inside and in between the
mesoderm cells disperse to points where they can make themselves useful
making bone and muscle and connective tissue that knits it all together.

This second tube will remain open at both ends throughout life, the brain
controlling them with varying degrees of success. <grin> A number of useful
organs develop along the route. (This is a very simplified expalantion and
Dr Peter will tell me if I've got it all wrong.)

1. So I suppose it's not suprising that sometimes a few cells end up with
the wrong instructions. Maybe Dr Peter can tell us. Did some of Emma's
abdominal lining cells lose the plot and think they were in a lung? Neil's
epidermoid cyst formed from skin cells which got left behind in the neural
tube.

2. Does something like this happen in edometriosis where some women have
womb lining cells in their abdominal cavity which react to hormones and
cause misery and discomfort?

3. Are these stray pieces of tissue more likely to become cancerous ... or
is it that we only hear about the ones that cause trouble?

It's still a miracle though, isn't it? ... Lizzie



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