how larg should my tissue sample be for western blotting? - (Jan/06/2007 )

Hi!
i am starting a research on oral cancer. and my samples are going to be analysed with western blot technique.
my question is how larg should my sample be for this job!
thanks.

20-40ug should be sufficient. I normally use 20. But it may depend upon your protein and the quality of your antibody.