Many of the tumor markers mentioned in this article may seem to be of only research or theoretic interest. However, many of those mentioned are likely to be of great clinical utility in the future. In particular, the strength of these immunohistochemical findings have been compared with standard clinical prognostic features (e.g., stage, age, B symptoms) and have been modeled to show independent prognostic relevance in both intermediate-grade and low-grade lymphomas. Beyond their predictive value, these markers have identified phenotypes that may serve as new therapeutic targets: (1) restoration of HLA loss with alpha and gamma interferons; and (2) restoration of tumor-infiltrating T-cell lymphocytes with interleukin-2. New phenotype-directed cytokine therapies seem compelling with this new knowledge. We await future prospective trials of phenotyping to further refine this new exciting prospect.