Alison H. Banham

Detection of elevated levels of tumour-associated microRNAs in serum of patients with diffuse large B-cell lymphoma.

Circulating nucleic acids have been shown to have potential as non‐invasive diagnostic markers in cancer. We therefore investigated whether microRNAs also have diagnostic utility by comparing levels of tumour‐associated MIRN155 (miR‐155), MIRN210 (miR‐210) and MIRN21 (miR‐21) in serum from diffuse large B‐cell lymphoma (DLBCL) patients (n = 60) with healthy controls (n = 43). Levels were higher in patient than control sera (P = 0·009, 0·02 and 0·04 respectively). Moreover, high MIRN21 expression was associated with relapse‐free survival (P = 0·05). This is the first description of circulating microRNAs and suggests that microRNAs have potential as non‐invasive diagnostic markers for DLBCL and possibly other cancers.

Quantification of Regulatory T Cells Enables the Identification of High-Risk Breast Cancer Patients and Those at Risk of Late Relapse

PURPOSE To assess the clinical significance of tumor-infiltrating FOXP3-positive regulatory T cells (TR) in breast cancer patients with long-term follow-up. PATIENTS AND METHODS FOXP3-positive TR were detected by immunohistochemistry with our new, extensively characterized FOXP3 monoclonal antibody, 236A/E7. Numbers of FOXP3-positive lymphocytes in tissue microarray cores from pure ductal carcinoma in situ (DCIS; n = 62), invasive breast cancer (n = 237) or from comparable areas of normal terminal duct lobular breast tissue (n = 10) were determined. A median cutoff of > or = 15 defined patients with high numbers of TR. RESULTS TR numbers were significantly higher in in situ and invasive breast carcinomas than in normal breast; invasive tumors have significantly higher numbers than DCIS (P = .001). High numbers of FOXP3-positive TR identified patients with DCIS at increased risk of relapse (P = .04) and patients with invasive tumors with both shorter relapse-free (P = .004) and overall survival (P = .007). High TR numbers were present in high-grade tumors (P < or = .001), in patients with lymph node involvement (P = .01), and in estrogen receptor (ER) -negative tumors (P = .001). Importantly, high numbers of TR within ER-positive tumors identified high-risk patients (P = .005). Unlike conventional clinicopathologic factors, high numbers of FOXP3-positive TR can identify patients at risk of relapse after 5 years. CONCLUSION These findings indicate that quantification of FOXP3-positive TR in breast tumors is valuable for assessing disease prognosis and progression, and that TR are an important therapeutic target for breast cancer. FOXP3-positive TR represent a novel marker for identifying late-relapse patients who may benefit from aromatase therapy after standard tamoxifen treatment.

Analysis of FOXP3 protein expression in human CD4+CD25+ regulatory T cells at the single-cell level.

The transcription factor FOXP3 plays a key role in CD4+CD25+ regulatory T cell function and represents a specific marker for these cells. Despite its strong association with regulatory T cell function, in humans little is known about the frequency of CD4+CD25+ cells that express FOXP3 protein nor the distribution of these cells in vivo. Here we report the characterization of seven anti‐FOXP3 monoclonal antibodies enabling the detection of endogenous human FOXP3 protein by flow cytometry and immunohistochemistry. Flow‐cytometric analysis showed that FOXP3 was expressed by the majority of CD4+CD25high T cells in peripheral blood. By contrast, less than half of the CD4+CD25int population were FOXP3+, providing an explanation for observations in human T cells that regulatory activity is enriched within the CD4+CD25high pool. Although FOXP3 expression was primarily restricted to CD4+CD25+ cells, it was induced following activation of both CD4+ and CD8+ T cell clones. These findings indicate that the frequency of FOXP3+ cells correlates with the level of expression of CD25 in naturally arising regulatory T cells and that FOXP3 protein is expressed by some activated CD4+ and CD8+ T cell clones. These reagents represent valuable research tools to further investigate FOXP3 function and are applicable for routine clinical use.

Outcome in Hodgkin's lymphoma can be predicted from the presence of accompanying cytotoxic and regulatory T cells.

Purpose: Recent studies of Hodgkins lymphoma (HL) have suggested that the presence of regulatory T cells in the reactive background may explain the inhibition of the antitumoral host immune response observed in these patients. This study aimed to assess the relevance of regulatory T cells and CTLs present in the background of HL samples in the prognosis of a series of classic HL (cHL) patients. Experimental Design: Expression of granzyme B and TIA-1 (markers for CTL) and FOXP3 (a marker for regulatory T cells) were evaluated independently by immunohistochemistry in tissue microarrays of 257 cHL patients and correlated with patient outcome. Results: The combined influence of the presence of FOXP3+ and TIA-1+ cells distinguished three risk groups of patients with 5-year overall survival of 100%, 88%, and 73%. The presence of a small number of FOXP3+ cells and a high proportion of TIA-1+ cells in the infiltrate represent an independent prognostic factor that negatively influenced event-free survival and disease-free survival in cHL. Compared with the features at diagnosis, relapsed samples tended to have more TIA-1+ cells and a lower proportion of FOXP3+ cells in the reactive background. Conclusions: These data suggest that low infiltration of FOXP3+ cells in conjunction with high infiltration of TIA-1+ cells in cHL may represent biological markers predicting an unfavorable outcome. Moreover, the variation of these markers over the course of the disease implies a possible role for them in the progression of HL cases.

CD4+CD25high T Cells Are Enriched in the Tumor and Peripheral Blood of Prostate Cancer Patients

In this study, we investigated whether CD4+CD25high regulatory T cells (Treg) are increased in the tumor tissue and peripheral blood of early-stage prostate cancer patients undergoing prostatectomy. We show that the prevalence of CD4+CD25high T cells inside the prostate was significantly higher in the tumor compared with benign tissue from the same prostate. Furthermore, the frequency of CD4+CD25high T cells in peripheral blood was significantly higher in prostate cancer patients compared with normal donors. A proportion of the CD4+CD25high T cells was also shown to be glucocorticoid-induced TNF receptor, ICOS, and FOXP3 positive. Moreover, CD4+CD25+ T cells from blood and supernatants from cultured prostate tumor tissue samples exhibited immunosuppressive function in vitro. Furthermore, supernatants from cultured prostate tissue samples and prostate cancer ascites fluid induced migration of CD4+CD25+ T cells and were shown to contain the regulatory T cell chemokine CCL22 by ELISA. Our findings indicate that Tregs are an important cellular component of early-stage prostate tumors, and thus new therapeutic strategies aimed at inhibition or depletion of Tregs may improve prostate cancer immunotherapy.

Expansion of CD4+CD25+and FOXP3+ Regulatory T Cells during the Follicular Phase of the Menstrual Cycle: Implications for Human Reproduction

Regulatory T cells (Tregs) are thought to affect the severity of various infectious and autoimmune diseases. The incidence of autoimmune disease is higher in fertile women than in men. Thus, we investigated whether Treg numbers were modulated during the menstrual cycle by sex hormones. In fertile nonpregnant women, we detected an expansion of CD4+CD25+FOXP3+ Tregs in the late follicular phase of the menstrual cycle. This increase was tightly correlated with serum levels of estradiol and was followed by a dramatic decrease in Treg numbers at the luteal phase. Women who have had recurrent spontaneous abortions (RSA) showed similarly low numbers of Tregs at both the follicular and luteal phases, comparable to numbers we observed in postmenopausal women. In addition to decreased numbers, Tregs from women with RSA were also functionally deficient, as higher numbers were required to exert a similar magnitude of suppression to CD4+CD25+FOXP3+ cells from fertile women. Consequently, reproductive failure might result from the inability of Tregs in women with RSA to expand during the preimplantatory phase combined with their lower functional capacity. Additionally, the modulation of Treg numbers we observed in fertile women suggests that the stage of the menstrual cycle should be taken into account when Treg numbers are investigated clinically.

Expression and functional characterization of FOXP3+CD4+ regulatory T cells in ulcerative colitis†

Background CD4+CD25+ regulatory T cells (TR) can prevent or treat experimental murine colitis but little is known about their potential role in human inflammatory bowel disease (IBD). FOXP3 is a transcription factor that plays a critical role in the development and function of CD4+CD25+ TR. The aim of this study was to examine the presence and functional characteristics of TR cells in colonic lymphoid tissues in patients with ulcerative colitis (UC). Methods FOXP3 expression was assessed by flow cytometry, immunohistochemistry, and reverse‐transcriptase polymerase chain reaction (RT‐PCR). Functional characterization of CD4+CD25+ cells was analyzed by suppression of proliferation and secretion of cytokines by cocultured effector CD4+CD25− T cells. Results FOXP3+CD4+ T cells are increased in the lamina propria (LP) of inflamed and noninflamed areas of UC colon compared to normal colon. CD4+CD25+ T cells in UC mesenteric lymph nodes (MLN) express FOXP3 mRNA and protein and suppress the proliferation of autologous MLN CD4+CD25− T cells. The suppressor activity of MLN CD4+CD25+ T cells is cell contact‐dependent but cytokine‐independent. In addition, CD4+CD25+ T cells potently suppress the production of both Th1 (IFN‐&ggr;, IL‐2) and Th2 (IL‐5, IL‐13) cytokines by cocultured CD4+CD25− T cells. FOXP3+ cells localized in the T‐cell‐rich areas of MLN and occasionally present in the follicles. Conclusions There is an expansion of FOXP3+CD4+ T cells in mucosal lymphoid tissues in UC. CD4+CD25+ isolated from UC MLN express FOXP3 and display features of TR cells in spite of active mucosal inflammation. These data suggest that their suppressor activity may be abrogated in vivo or they are unable to counterbalance the chronic mucosal inflammation in UC. (Inflamm Bowel Dis 2007)

FOXP3+ regulatory T cells: Current controversies and future perspectives

Regulatory T cells (Treg) provide protection from autoimmune disease, graft‐versus‐host disease, transplant rejection and overwhelming tissue destruction during infections. Conversely, high Treg numbers enable cancer cells to evade the host immune response. Thus, Treg are seen as an important tool to manipulate the immune response. However, as the immunological community is trying to move this knowledge from mice to humans, contradictory results regarding the number and function of Treg in various diseases are appearing. This problem arises because we cannot clearly define Treg populations on the basis of expression of CD25 and other cell surface markers in humans. This review addresses the utility of the FOXP3 forkhead transcription factor for the identification of Treg populations and summarizes recent data on the expression of FOXP3 in lymphomas. It is crucial to really understand Treg biology before attempting therapies, including (i) the injection of expanded Treg to cure autoimmune disease or prevent graft‐versus‐host disease or (ii) the depletion or inhibition of Treg in cancer therapy. For instance, new data arising from the study of haematological malignancies highlight the additional complexity of systems where malignant cell populations may also be direct Treg targets.

FOXP3, a selective marker for a subset of adult T-cell leukaemia/lymphoma.

FOXP3 is a forkhead transcription factor family member, implicated in T-cell regulation, activation and differentiation. FOXP3 has been shown to be a master control gene for the development and function of CD4+/CD25+ regulatory T-cells (Treg). In this study, FOXP3 protein expression has been analysed using a new anti-FOXP3 monoclonal antibody in 172 paraffin-embedded lymphoma samples. FOXP3 expression in tumour cells was confined to adult T-cell leukaemia/lymphoma (ATLL) cases (17/25, 68%), with some variability in the intensity of the staining and the proportion of positive cells. No other lymphoma types studied exhibited FOXP3 expression in the malignant population. The selective expression of FOXP3 by tumour cells in ATLL makes this antibody a potentially useful diagnostic tool.

FOXP1: A potential therapeutic target in cancer

Forkhead Box P1 (FOXP1) is a member of the FOX family of transcription factors which have a broad range of functions. Foxp1 is widely expressed and has been shown to have a role in cardiac, lung and lymphocyte development. FOXP1 is targeted by recurrent chromosome translocations and its overexpression confers a poor prognosis in a number of types of lymphomas, suggesting it may function as an oncogene. In contrast, FOXP1 localises to a tumour suppressor locus at 3p14.1 and loss of FOXP1 expression in breast cancer is associated with a worse outcome, suggesting FOXP1 may function as a tumour suppressor in other tissue types. These data suggest that FOXP1 may not only be useful in prognosis but also may be used to develop FOXP1-directed therapeutic strategies.