[BioC] Siggenes: How to deal with one treatment - five controls problem?

[Paolo Sirabella]

Hi,
I have a very raw question ... 
The following refers to a subset of a more complex data-set: I have 5 affy
arrays (controls: A,B,C,D,P2), corresponding to 2 donors (A,B,C,D) and a
pool of other 4 different donors (P2). Besides, I have ONE SINGLE ARRAY
(treatment: P4) corresponding to a pool of 4 donors (two of them are the
same of the P2 array).

Summarizing: (controls: A,B,C,D,P2) (treatment: P4)

I know, it is a very poor data-set .. but I need to analyze it the same .. I
planned to use siggenes (two class unpaired), but, correctly, a warning
popped-up with the message that 'Each group must consist of at least two
samples.' 
Now I am spending my holidays - yes, working at microarray analysis! - and I
am far from my lab, from the library and from my handbooks. 

Which is, in this case, the more appropriate approach (excluding the
hypothesis, up to now, of expanding the data-set ..)?

Thank you in advance, and sorry for the .. raw question.

Paolo Sirabella
psirab at libero.it