What are some of the limitations of FISH and IHC cancer diagnosis?

FISH only shows you grossly if there have been large chromosomal deletions or rearrangements. Likewise IHC or immunohistochemistry is looking for gross alterations in protein expression of localization. Meanwhile, newer molecular tools can give precise genotypic information on a cancer, which can be correlated to a phenotype. There remains a role for all of these test in cancer diagnosis.