The main project involves the study of breast carcinoma as part of the NCI Black/White Cancer Survival Study in which behavioral and biologic variables have been studied to account for the racial disparity in survival between African-American and Caucasian women. Several molecular, biologic and clinical parameters have been studied, including loss of heterozygosity (LOH), cerbB-2, estrogen receptor status, and five year survival. Using a modified microdissection technique, devised by Drs. Emmert-Buck and Zhuang, DNA analysis was performed to investigate LOH on chromosome 11q13 and 17q21-23 for breast carcinoma cases in which material was limited to formalin-fixed, paraffin-embedded sections. In the past year, data collection was completed and this exploratory study was unmasked for statistical and epidemiologic analysis. An analysis of 61 informative cases from the NCI Black/White study cohort, approximately 30 from each race, was performed. The overall rate of LOH for informative cases was 43% (26 of 61). Early clinical stage (stage I and IINO) comprised 23% (5 of 23) of LOH cases. LOH increased with high stage (IIN1), III or IV); 54% (21 of 39) of high stage cases demonstrated LOH (p = .02, adjusted for race and age group). LOH correlated with race (p = .05, adjusted for stage and age). Estrogen receptor status, c-erbB-2, and 5 year survival were not related to LOH. LOH on chromosome 11q13 was correlated with higher stage breast carcinoma and showed a greater association with high stage for African-American women than Caucasian women. This pilot study justifies expanded studies to investigate the correlation with stage and clinical outcome. The other project involves an epidemiologic search and analysis of the NCI Surveillance, Epidemiology, End Result (SEER) database to investigate demographic variables associated with neuroendocrine tumors, a subject for which there is no comparable information from large scale study in the medical literature. If this project is contributory to the biologic studies, similar database searches for other neoplasms of particular research interest in the Laboratory of Pathology may be undertaken.