to improve diagnosis; and defining the signature of cancer cells to improve detection and diagnosis (National Cancer Institute, 1998d).
New developments in basic research have led to groundbreaking cancer treatments and prevention methods that have provided benefits to all populations. In some cases, significant gains have been made in technologies for the detection and treatment of cancers that disproportionately affect ethnic minority and medically underserved populations. Few examples of basic research at NCI dedicated to examinations of potential differences in underlying biological or genetic mechanisms among population groups exist, however. In a document provided to the study committee, NCI reports that "where there are biological differences among populations, these can only be found through basic research," yet it goes on to state that its "basic science projects are rarely categorized as 'targeted' research" (National Cancer Institute, 1998b, p. 80).
NCI provided to the study committee examples of ongoing basic research that may provide benefits for the detection, prevention, and treatment of several cancers that disproportionately affect ethnic minority and elderly populations. Only in the area of breast cancer was it apparent that research questions were directed toward understanding population-group differences in cancer etiologies, disease courses, and treatment responses. For example, NCI has initiated a study to investigate the reasons for the possible increased aggressiveness of breast cancer in African-American women. Analyses of breast tissue samples from African-American and white patients matched by age, stage of disease at diagnosis, and other critical factors are under way to determine if differences in molecular characteristics may account for the poorer prognosis of breast cancer in African-American women. In addition, NCI has supported research on Mapping by Admixture Linkage Disequilibrium (MALD) to assist in gene mapping among patients with sporadic cases of breast cancer. Such patients have no family history of the disease, precluding traditional genetic linkage analysis. Tissue specimens from African-American patients are being analyzed by MALD analysis to explore possible genetic links behind sporadic cases of breast cancer.
NCI is also supporting two pilot studies involving basic research on breast cancer among diverse population groups. One examines the kinetics as the well as the phenotypic and genotypic properties of breast cancer as they relate to tumor aggressiveness among African-American, Hispanic, and white women in south Florida. Another plans a comparative molecular analysis of the primary DNA sequence of the estrogen receptor gene in breast cancer tissue removed from African-American, Hispanic, and white women to look for potential gene rearrangements and deletions.