The use of computer-assisted image analysis in the evaluation of preclinical tumor efficacy models.

: Quantitation in histopathology generates numerical or rank-order data amenable to statistical analysis, but can be very labor-intensive. The advent and coupling of computerized image analysis systems and optimized immunostaining procedures has not only decreased the laborious aspect of counting, but has also improved reproducibility and reliability by overcoming inter- and intra-observer variation. Still, a certain degree of manual intervention is required and a good understanding of the underlying biology is mandatory for proper design of the sampling system. Here, we focus on subcutaneous tumor models to illustrate the use and benefits of computer-assisted image analysis in quantitative histopathology. In particular, we discuss the quantitation of biological parameters frequently assessed in biology and toxicology: cell proliferation, apoptotic and oncotic necrosis, and angiogenesis. For each of these parameters, specific sampling procedures and labeling techniques are discussed based on current molecular and cellular concepts.