Advances in cell and molecular biology have engendered a wide range of tech
niques that can be used to study the molecular events that underlie the cau
se of disease, thus producing a new field of study called "molecular pathol
ogy." These techniques can be either slide-based or non-slide-based (soluti
on-based). The slide-based techniques include immunohistochemistry, in situ
hybridization, and in situ polymerase chain reaction; pathologists play a
unique role in the administration of these techniques because of their abil
ity to interpret the end product (i.e., the slide). In this manuscript, we
briefly discussed the use and impact of these slide-based techniques within
all phases of drug development in the pharmaceutical industry.