March 25, 2011


It was a clever chemist that decided to call 5-fluorouracil FU.

FU! is the name of my chemotherapeutic. I have a bottle of it attached to my arm connected to a tube that leads to my heart. FU! sits in a balloon in this bottle and slowly enters my body at 0.5 ml per hour, 24-7.

FU! is toxic to certain types of cells and is called cytotoxic ('cyto' is fancy for 'cell'). It targets cells that are dividing quickly. Cancer cells divide quickly because they are out of control and no longer follow the rules of the body.

It turns out that cells dividing quickly and frequently need a lot of uracil (this is the U in FU!). FU! is like uracil in disguise.

The disguise

FU! looks like normal uracil, but it has switched one of its hydrogen atoms for a fluorine one (the F in FU!). That's the only difference between the uracil in disguise (FU!) and genuine uracil - but that one change means it causes havoc inside cells.

The impostor gets messy

FU! looks enough like uracil to get inside a cell, but it isn't uracil, and so when the cell tries to use it things go wrong. The cell converts FU! into several different molecules that then interfere with how the cell copies DNA.

Remember that FU! has to look enough like uracil to get this far, otherwise the cell would break it down and clear it out. Clever FU!.

Dumb FU!

Cancer cells divide frequently, but so do cells in the mouth, intestines, heart and immune system. FU! dresses up and tries to get into any cell that needs uracil. This leads to a long list of potential chemotherapy side effects that include mouth ulcers, a weak immune system and bot-bot troubles.

I've had all three.

5-Fluorouracil (5FU)

1 comment:

  1. I remember learning about 5FU in 'cellular and medical biochem'. By getting right to the heart of the cell's signalling and worker chemicals (RNAs) it has such an elegant mechanism for screwing up fast-dividing cells. Mwa ha ha...