Pancreatic Polypeptide Cell Proliferation in the Pancreas and Duodenum Coexisting in a Patient With Pancreatic Adenocarcinoma Treated With a GLP-1 Analog.

A partial pancreaticogastrodudenectomy was performed on a 66-year old man with type 2 diabetes mellitus because of an invasive, moderately differentiated adenocarcinoma in the head of the pancreas. In the adjacent grossly normal tissue of the uncinate process, there was a massive proliferation of pancreatic polypeptide (PP) cells confined to this region and showed invasive pattern. Strikingly, in the heaped area of his duodenum, there was a strikingly large number of PP, glucagon, a few insulin cells in a mini-islet-like patterns composed of glucagon and insulin cells. Among the etiological factors, the possible long-lasting effects of the GLP-1 analog, with which the patient was treated, are discussed. This is the first report in the literature of both the coexistence of a pancreatic adenocarcinoma and invasive PPoma and the occurrence of PP and insulin cells in human duodenal mucosa.

Evaluating one day versus two days preoperative lymphoscintigraphy protocols for sentinel lymph node biopsy in breast cancer.

Sentinel lymph node biopsy (SLNB) is used to detect axillary lymph node metastases in breast cancer. Preoperative radiocolloid injection with lymphoscintigraphy (PL) is performed before SLNB. Few comparisons between 1- and 2-day PL protocols exist. Opponents of a 2-day protocol have expressed concerns of radiotracer washout to nonsentinel nodes. Proponents cite lack of scheduling conflicts between PL and surgery. A total of 387 consecutive patients with clinically node-negative breast cancer underwent SLNB with PL. Lymphoscintigraphy images were obtained within 30 minutes of radiocolloid injection. Axillary lymph node dissection was performed if the sentinel lymph node (SLN) could not be identified. Data were collected regarding PL technique and results. In all, 212 patients were included in the 2-day PL group and 175 patients in the 1-day PL group. Lymphoscintigraphy identified an axillary sentinel node in 143/212 (67.5%) of patients in the 2-day group and 127/175 (72.5%) in the 1-day group (P = 0.28). SLN was identified at surgery in 209/212 (98.6%) patients in the 2-day group and 174/175 (99.4%) in the 1-day group (P = 0.41). An average of 3 SLN was found at surgery in the 2-day group compared with 3.15 in the 1-day group (P = 0.43). SLN was positive for metastatic disease in 54/212 (25.5%) patients in the 2-day group compared with 40/175 (22.9%) in the 1-day group (P = 0.55). A 2-day lymphoscintigraphy protocol allows reliable detection of the SLN, of positive SLN and equivalent SLN harvest compared with a 1-day protocol. The timing of radiocolloid injection before SLNB can be left at the discretion of the surgeon.

Radiofrequency ablation of lung malignancies.

Radiofrequency ablation is a new technology that has been used successfully to treat hepatic tumors. Recently, an increasing number of reports have described the use of radiofrequency ablation for primary and metastatic lung tumors. Although such early experience appears promising, many questions regarding patient selection, radiofrequency ablation technique, effectiveness of ablation on lung tumors, radiographic follow-up, and survival remain unanswered. This article addresses these issues and provides the thoracic surgeon with a current review of the application of radiofrequency ablation to lung tumors.

Radiofrequency ablation of primary lung cancer: results from an ablate and resect pilot study.

STUDY OBJECTIVES: The role of radiofrequency ablation (RFA) for primary lung cancer remains poorly defined. The purpose of this "ablate and resect" pilot study was to evaluate the safety of performing RFA in patients with primary non-small cell lung cancer (NSCLC) and to characterize the histologic changes in tumor tissue following such ablation. DESIGN: This prospective study was undertaken at a single institution, and 10 patients were accrued from June 2002 to June 2003. Eligible patients included those with clinical stage I or II disease. RFA of the tumor was performed through a standard thoracotomy followed by conventional lobectomy and lymph node dissection. Extent of cell death was determined histologically. MEASUREMENTS AND RESULTS: Following the exclusion of two patients, the treated portions of eight tumors were examined for tumor cell viability. Gross inspection and routine histologic staining could not reliably identify the "immediately ablated" tissue. However, using a supravital staining technique, the treated areas from seven of the eight tumors (87.5%) demonstrated > 80% nonviability (100% nonviability was noted in the treated areas from three of the eight tumors). No bleeding or thermal complications were noted at the time of RFA, and none of the patients had skin burns at the electrode dispersive pad sites. CONCLUSIONS: RFA of primary NSCLC is feasible and can be performed safely in the setting of an open thoracotomy. Complete tumor cell necrosis, as determined by supravital staining, was noted in the treated areas from three of eight tumors (37.5%). Such complete ablation was observed in the treated areas from smaller tumors (< 2 cm), whereas the treated areas from larger tumors demonstrated incomplete ablation. Additional investigation with histopathologic correlation is needed to fully assess the long-term efficacy of RFA for NSCLC.

Paracrine release of IL-12 stimulates IFN-gamma production and dramatically enhances the antigen-specific T cell response after vaccination with a novel peptide-based cancer vaccine.

Interleukin-12 can act as a potent adjuvant for T cell vaccines, but its clinical use is limited by toxicity. Paracrine administration of IL-12 could significantly enhance the response to such vaccines without the toxicity associated with systemic administration. We have developed a novel vaccine delivery system (designated F2 gel matrix) composed of poly-N-acetyl glucosamine that has the dual properties of a sustained-release delivery system and a potent adjuvant. To test the efficacy of paracrine IL-12, we incorporated this cytokine into F2 gel matrix and monitored the response of OT-1 T cells in an adoptive transfer model. Recipient mice were vaccinated with F2 gel/SIINFEKL, F2 gel/SIINFEKL/IL-12 (paracrine IL-12), or F2 gel/SIINFEKL plus systemic IL-12 (systemic IL-12). Systemic levels of IL-12 were lower in paracrine IL-12-treated mice, suggesting that paracrine administration of IL-12 may be associated with less toxicity. However, paracrine administration of IL-12 was associated with an enhanced Ag-specific T cell proliferative and functional response. Furthermore, paracrine IL-12 promoted the generation of a stable, functional memory T cell population and was associated with protection from tumor challenge. To study the mechanisms underlying this enhanced response, wild-type and gene-deficient mice were used. The enhanced immune response was significantly reduced in IFN-gamma(-/-) and IL-12R beta 2(-/-) recipient mice suggesting that the role of IL-12 is mediated, at least in part, by host cells. Collectively, the results support the potential of F2 gel matrix as a vaccine delivery system and suggest that sustained paracrine release of IL-12 has potential clinical application.

Mechanisms of enhanced antigen-specific T cell response following vaccination with a novel peptide-based cancer vaccine and systemic interleukin-2 (IL-2).

Systemic interleukin-2 (IL-2) therapy has been shown to enhance the clinical efficacy of peptide-based cancer vaccines. However, the mechanisms involved in this complex response remain poorly defined. IL-2 is known to be a potent T cell growth factor, but recent studies suggest that IL-2 is also involved in the regulation of T cell immune responses by increasing the susceptibility of proliferating T cells to apoptosis. Using an adoptive transfer model, we demonstrate that the administration of systemic IL-2 significantly enhances the primary and memory immune responses following peptide-based vaccination. In order to define the mechanisms of IL-2 therapy on the antigen-specific T cell response, the kinetics of T cell proliferation, apoptosis, and trafficking were explored. Systemic IL-2 therapy did not appear to alter the kinetics of T cell proliferation immediately following vaccination, but did prolong the proliferative response. Furthermore, IL-2 therapy did not significantly influence apoptosis of proliferating T cells. Such therapy did, however, potentiate L-selectin (CD62L) downregulation on activated antigen-specific T cells, and altered their trafficking confirming their potential therapeutic value. Our findings support the use of systemic IL-2 following peptide-based vaccination, and suggest that IL-2 therapy enhances the primary and memory immune responses by prolonging the proliferative response and altering the trafficking of antigen-specific T cells.

Transfer of TCR genes into mature T cells is accompanied by the maintenance of parental T cell avidity.

The adoptive transfer of tumor-specific T cells expanded in vitro can be of significant therapeutic value in select cancer patients. This strategy is limited though, as it is often difficult, if not impossible, to obtain T cells of clinical value. The transfer of TCR genes to mature T cells to generate tumor-reactive T cells provides a potential mechanism to overcome these limitations. To evaluate the feasibility of such an approach and the quality of the resulting T cells, we generated replication-deficient retroviral vectors using the well-characterized OT-1 TCR genes. After transducing murine T cells, we were able to expand large numbers of Ag-specific T cells that were functionally active against tumor cells expressing the relevant Ag. Furthermore, we found that T cells expressing retrovirally encoded TCR had avidity that was similar to that of the parental clone. This maintenance of avidity was despite variable expression of the retrovirally encoded TCR and the presence of potentially competing endogenous TCRs. These results suggest that the inherent qualities of the TCR, as dictated by the coding sequence, are the most critical parameters in the generation of high-avidity T cells.

Systemic administration of IL-15 augments the antigen-specific primary CD8+ T cell response following vaccination with peptide-pulsed dendritic cells.

The systemic administration of IL-2 can act as a potent adjuvant for T cell-directed vaccine strategies. However, not only is the administration of IL-2 potentially toxic, but recent evidence suggests that it may also paradoxically limit the duration and magnitude of the cytotoxic T cell response. A recently identified cytokine, IL-15, shares many properties with IL-2 and may provide a preferential means of augmenting T cell-directed vaccine responses. Although well characterized in vitro, there are few data on the ability of IL-15 to augment T cell-mediated responses in vivo. We therefore evaluated the ability of systemic IL-15 to function as a T cell adjuvant in a murine vaccine model. To establish a population of easily identifiable Ag-responsive T cells, naive CD8(+) (OT-1) T cells were first adoptively transferred into mice. Vaccination with peptide-pulsed dendritic cells induced a modest expansion of OT-1 T cells. The addition of systemic IL-15 for 7 days following vaccination resulted in a significant increase in the expansion of responding T cells in the PBL, spleen, and lymph nodes. Importantly, the responding T cells were cytotoxic and maintained a Tc1-biased phenotype. We did not observe either enhanced resistance to activation-induced cell death or preferential generation of memory T cells as a result of treatment with IL-15 compared with IL-2. These studies show for the first time that IL-15 is capable of augmenting the primary CD8(+) T cell response to vaccination and contribute to the basis for future experiments exploring the clinical role of IL-15.

Sustained Release of Granulocyte-Macrophage Colony-Stimulating Factor From a Modular Peptide-Based Cancer Vaccine Alters Vaccine Microenvironment and Enhances the Antigen-Specific T-Cell Response.

SUMMARY: The recent identification and molecular characterization of tumor antigens provides the opportunity to explore the rational development of peptide-based cancer vaccines. However, the response to these vaccines remains variable, and peptide-based cancer vaccines may even produce tolerance induction and enhanced tumor growth. The authors have developed a unique method for the isolation of a polysaccharide polymer of chemically pure poly- N -acetyl glucosamine (p-GlcNAc). This highly purified polysaccharide can be formulated into a stable gel matrix (designated F2 gel matrix) with unique properties of a sustained-release delivery system that has previously been shown to be an effective immune adjuvant. F2 gel matrix is capable of providing sustained release of antigenic peptide and cytokine in vitro. The purposes of this study were to characterize the ability of F2 gel matrix to provide sustained local release of cytokines in vivo and to test the hypothesis that such sustained release can enhance the microenvironment for antigen presentation, leading to a more effective antitumor response. Subcutaneous administration of F2 gel/cytokine matrix resulted in sustained release of cytokine at the vaccine site for up to 120 hours. Sustained release of granulocyte-macrophage colony-stimulating factor (GM-CSF) was associated with an increased inflammatory infiltrate at the vaccine site and enhanced dendritic cell activation. Further, accination with F2 gel/SIINFEKL/GM-CSF matrix resulted in enhanced antigen-specific immunity. Addition of GM-CSF to the F2 gel matrix resulted in an increase in the percentage of antigen-specific T cells in the draining lymph nodes, enhanced cytotoxicity, a sustained presence of antigen-specific T cells in the peripheral blood, and protection from E.G7 tumor challenge. These results support the potential of an F2 gel matrix modular vaccine delivery system that can provide sustained local release of cytokine in vivo, and confirm the powerful effects of GM-CSF as an immune adjuvant.