CONFOCAL LASER-SCANNING MICROSCOPY IN CYTOPATHOLOGY

Confocal laser scanning microscopy (CLSM) has become an exciting new i nstrument with rapidly expanding potential for application to the morp hological examination. As an initial step of examining the possible va lues or potentials of CLSM observations in diagnostic pathology materi als, we applied CLSM to the analysis of immunolocalization of prolifer ating cell nuclear antigen (PCNA), p53 and cytokeratin, and eosin and DNA fluorochrome propidium (PI) stain in cell smears obtained from 20 cases of squamous cell carcinoma of the esophagus. Superior contrasts and resolution were obtained in confocal images than in nonconfocal on es in immunocytochemistry, eosin, and PI stain. In immunocytochemistry , CLSM demonstrated subcellular localization of antigens examined, cyt okeratin as coarse and fine intracytoplasmic fibers, PCNA as diffuse i ntranuclear localization, and p53 as heterogeneous intranuclear locali zation which appeared to be associated with chromatin structure. Optic al sectioning of a specimen by the rejection of out-of-focus noise rev ealed three dimensional structure of cell clusters of squamous cell ca rcinoma. With eosin and PI as dyes for stain, three dimensional struct ures of any clusters on cell smears can be obtained. CLSM has vast pot entials in the analysis of diagnostic cytology materials, including im munocytochemistry.