Minimax two-stage-designs with applications to tissue banking case-control studies.

'Tissue banks' are created, at least in part, to help medical scientists learn about disease biology on the basis of samples provided by patients on treatment protocols that were competed years earlier. The bank inventory consists of precious non-renewable patient material (such as frozen diagnostic blood or bone marrow), which can be linked to both clinical data and long term follow-up information. Case-control studies, where cases represent clinical failures and controls clinical successes, are ideal for rapidly learning if a laboratory marker might have prognostic significance.