The use of molecular profiling to predict survival after chemotherapy for diffuse large-B-cell lymphoma.

BACKGROUND: The survival of patients with diffuse large-B-cell lymphoma after chemotherapy is influenced by molecular features of the tumors. We used the gene-expression profiles of these lymphomas to develop a molecular predictor of survival. METHODS: Biopsy samples of diffuse large-B-cell lymphoma from 240 patients were examined for gene expression with the use of DNA microarrays and analyzed for genomic abnormalities. Subgroups with distinctive gene-expression profiles were defined on the basis of hierarchical clustering. A molecular predictor of risk was constructed with the use of genes with expression patterns that were associated with survival in a preliminary group of 160 patients and was then tested in a validation group of 80 patients. The accuracy of this predictor was compared with that of the international prognostic index. RESULTS: Three gene-expression subgroups--germinal-center B-cell-like, activated B-cell-like, and type 3 diffuse large-B-cell lymphoma--were identified. Two common oncogenic events in diffuse large-B-cell lymphoma, bcl-2 translocation and c-rel amplification, were detected only in the germinal-center B-cell-like subgroup. Patients in this subgroup had the highest five-year survival rate. To identify other molecular determinants of outcome, we searched for individual genes with expression patterns that correlated with survival in the preliminary group of patients. Most of these genes fell within four gene-expression signatures characteristic of germinal-center B cells, proliferating cells, reactive stromal and immune cells in the lymph node, or major-histocompatibility-complex class II complex. We used 17 genes to construct a predictor of overall survival after chemotherapy. This gene-based predictor and the international prognostic index were independent prognostic indicators. CONCLUSIONS: DNA microarrays can be used to formulate a molecular predictor of survival after chemotherapy for diffuse large-B-cell lymphoma.

Immunity from smallpox vaccine persists for decades: a longitudinal study.

PURPOSE: The threat of smallpox resulting from bioterrorist action has prompted a reassessment of the level of immunity in current populations. METHODS: We have examined the magnitude and duration of antiviral antibody immunity conferred by smallpox vaccination in 246 participants of the Baltimore Longitudinal Study of Aging. Of this population, 209 subjects were vaccinated one or more times 13 to 88 years before this evaluation, and stored serum samples were available at various intervals after vaccination. An additional 8 subjects who had documented childhood smallpox infection and 29 subjects with no history of infection or vaccination were included. We quantified the total vaccinia IgG and neutralizing antibody titers in each of these subgroups of participants over time. RESULTS: Vaccinated participants maintained antivaccinia IgG and neutralizing antibody titers above 3 natural logs essentially indefinitely. The absolute titer of antivaccinia antibody was only slightly higher after multiple vaccinations. In 97% of the participants, no decrease in vaccinia-specific antibody titers was noted with age over a follow-up period of up to 88 years. Moreover, Baltimore Longitudinal Study of Aging participants who survived active smallpox infections in their youth retained antivaccinia antibody titers that were similar to the levels detected in vaccinated subjects. CONCLUSION: These data suggest that multiple or recent vaccinations are not essential to maintain vaccinia-specific antibody responses in human subjects. Scarce vaccine supplies should be applied first to individuals who have not previously been vaccinated.

Informed consent for research participation in frail older persons.

Informed consent has been the most scrutinized and controversial aspect of clinical research ethics. Institutional review boards (IRBs), government regulatory agencies, and the threat of litigation have all contributed to increasingly detailed consent documents that hope to ensure that subjects are not misled or coerced. Unfortunately, the growing regulatory burden on researchers has not succeeded in protecting subjects, but has rather made the consent process less effective and has discouraged research on vulnerable populations. As a matter of fact, investigators and ethicists continue to identify failures of the consenting process, particularly concerning participation in research of older individuals. The challenges involved in ensuring appropriate consent from the elderly include physical frailty, reduced autonomy and privacy, and impaired decision-making capacity due to dementia, delirium, or other neuropsychiatric illnesses. Ageism among investigators also contributes to failure of informed consent. The evaluation and continuing re-evaluation of an individual's decision-making capacity is critical but difficult. In the most extreme cases, the older adult's ability to participate in the consent process is clearly impaired. However, in many instances, the decision-making capacity is only partially impaired but declines during the course of a research project. Implementing methods of effective communication may enable many frail elderly individuals to make informed decisions. Special challenges are posed by research on end-of-life care, which typically involves frail, older subjects who are uniquely vulnerable, and research is conducted in institutional settings where subtle violations of autonomy are routine. Clearly, the frail elderly represent a vulnerable population that deserves special attention when developing and evaluating an informed consent process. Two important ethical conflicts should be kept in mind. First, although vulnerable older patients must be protected, protection should not prevent research on this important population. Similarly, because informed consent documents are often written to prevent legal jeopardy, these technical documents, expressed in language sometimes difficult to understand, can prevent comprehension of basic issues, defeating the ethical purpose of human protection.