The Research Cytogenetics and Laser Capture Microdissection (RCLC) Facility provides karyolyping, molecular cytogenetic analyses, and Laser Capture Microdissection (LCM). The RCLC Facility, established in July 1995, is used by Members of all three FCCC Divisions from 11 research Programs. The Facility supported 29 funded investigators over the last five years. In addition to offering a full spectrum of cytogenetic services, the RCLC Facility has added multiplex-fluorescence In situ hybridization FISH (M-FISH) for analysis of structural rearrangements and array-comparative genomic hybridization (array-CGH) for analysis of DNA copy number changes in tumor specimens and cell lines. Two complete LCM workstations are now available, including a new AutoPix LCM apparatus (Arcturus) that provides rapid and convenient access to pure cell populations through a totally automated system. The LCM component is managed by a trained pathologist. The Facility Director is the Program Leader of Human Genetics and the cytogenetics component is managed by an experienced and skilled cytogeneticist. In 2003, the number of tests performed by the Research Cytogenetics component increased nearly four-fold compared to that carried out in 1999, when this was a Developing Core Facility. In 1999, we performed conventional FISH mapping and karyotypic and CGH analyses on 20 samples, whereas in 2003, 73 samples were analyzed, an increase of 265%. From the time when LCM services were first introduced in the RCLC Facility four years ago, LCM usage has increased from 150 hours in 2000 to 570 hours in 2003, an increase of 280%. The percentage of the Facility's operating budget supported by user's fees increased from 11% in 1999 to 20% in 2003. Although demand for FISH mapping of native gene loci has virtually ended, requests increased by 160% for FISH analysis of structural rearrangements or viral/transgene integration sites, interphase FISH to identify genomic alterations in non-dividing cells, and chromosome painting and M-FISH to facilitate interpretation of complex or subtle chromosome rearrangements. In addition, requests for karyotyping of embryonic stem cell clones used in mouse model studies is a new frequent demand averaging 24 requests per year.