Toward the molecular dissection of peritoneal pseudomyxoma.

BACKGROUND: Outcome of pseudomyxoma peritonei (PMP) after cytoreductive surgery (CRS) and hypertermic intraperitoneal chemotherapy (HIPEC) is heterogeneous even after adjusting for clinico-pathological prognostic variables. The identification of additional prognostic or even predictive biomarkers is an unmet clinical need. PATIENTS AND METHODS: Forty patients with mucinous appendiceal tumors and PMP were clinically eligible and had evaluable tumor samples obtained after CRS and HIPEC. We carried out next-generations sequencing (NGS) of 50 gene's hotspot regions contained in the Hotspot Cancer Panel v2 using the Ion Torrent Personal Genome Machine platform (Life Technologies). RESULTS: KRAS and GNAS mutations were found in 72% and 52%, and their allelic frequency was below 10% in 55% and 43% of samples, respectively. KRAS and GNAS mutations were associated with worse progression-free survival (PFS) at univariate analysis (P = 0.006 and 0.011, respectively). At multivariate analysis, only KRAS mutations were independently associated with PFS (P = 0.012); GNAS mutations were not-being significantly associated with other poor prognostic features such as incomplete cytoreduction or KRAS mutations. Validation of results was carried out in an independent bi-institutional cohort of 25 patients and the prognostic effect of KRAS mutations was again confirmed in the multivariate model (P = 0.029). NGS approach allowed the discovery of other potentially druggable mutations such as those in PI3K, AKT, LKB1, FGFR3 and PDGFRA. CONCLUSIONS: Given the homogeneity of this series and the sensitivity of NGS in this low-cellularity tumor, we demonstrated for the first time a poor prognostic role of KRAS mutations.

Heteroclitic immunization induces tumor immunity.

In tumor transplantation models in mice, cytotoxic T lymphocytes (CTLs) are typically the primary effector cells. CTLs recognize major histocompatibility complex (MHC) class I-associated peptides expressed by tumors, leading to tumor rejection. Peptides presented by cancer cells can originate from viral proteins, normal self-proteins regulated during differentiation, or altered proteins derived from genetic alterations. However, many tumor peptides recognized by CTLs are poor immunogens, unable to induce activation and differentiation of effector CTLs. We used MHC binding motifs and the knowledge of class I:peptide:TCR structure to design heteroclitic CTL vaccines that exploit the expression of poorly immunogenic tumor peptides. The in vivo potency of this approach was demonstrated using viral and self-(differentiation) antigens as models. First, a synthetic variant of a viral antigen was expressed as a tumor antigen, and heteroclitic immunization with peptides and DNA was used to protect against tumor challenge and elicit regression of 3-d tumors. Second, a peptide from a relevant self-antigen of the tyrosinase family expressed by melanoma cells was used to design a heteroclitic peptide vaccine that successfully induced tumor protection. These results establish the in vivo applicability of heteroclitic immunization against tumors, including immunity to poorly immunogenic self-proteins.

Coupling and uncoupling of tumor immunity and autoimmunity.

Self-antigens, in the form of differentiation antigens, are commonly recognized by the immune system on melanoma and other cancers. We have shown previously that active immunization of mice against the melanocyte differentiation antigen, a tyrosinase-related protein (TRP) gp75(TRP-1) (the brown locus protein) expressed by melanomas, could induce tumor immunity and autoimmunity manifested as depigmentation. In this system, tumor immunity and autoimmunity were mediated by autoantibodies. Here, we characterize immunity against another tyrosinase family glycoprotein TRP-2 (the slaty locus protein), using the same mouse model and method of immunization. As observed previously for gp75(TRP-1), immunity was induced by DNA immunization against a xenogeneic form of TRP-2, but not against the syngeneic gene, and depended on CD4(+) cells. Immunization against TRP-2 induced autoantibodies and autoreactive cytotoxic T cells. In contrast to immunization against gp75(TRP-1), both tumor immunity and autoimmunity required CD8(+) T cells, but not antibodies. Only autoimmunity required perforin, whereas tumor immunity proceeded in the absence of perforin. Thus, immunity induced against two closely related autoantigens that are highly conserved throughout vertebrate evolution involved qualitatively different mechanisms, i.e., antibody versus CD8(+) T cell. However, both pathways led to tumor immunity and identical phenotypic manifestations of autoimmunity.

Tumor immunity and autoimmunity induced by immunization with homologous DNA.

The immune system can recognize self antigens expressed by cancer cells. Differentiation antigens are prototypes of these self antigens, being expressed by cancer cells and their normal cell counterparts. The tyrosinase family proteins are well characterized differentiation antigens recognized by antibodies and T cells of patients with melanoma. However, immune tolerance may prevent immunity directed against these antigens. Immunity to the brown locus protein, gp75/ tyrosinase-related protein-1, was investigated in a syngeneic mouse model. C57BL/6 mice, which are tolerant to gp75, generated autoantibodies against gp75 after immunization with DNA encoding human gp75 but not syngeneic mouse gp75. Priming with human gp75 DNA broke tolerance to mouse gp75. Immunity against mouse gp75 provided significant tumor protection. Manifestations of autoimmunity were observed, characterized by coat depigmentation. Rejection of tumor challenge required CD4(+) and NK1.1(+) cells and Fc receptor gamma-chain, but depigmentation did not require these components. Thus, immunization with homologous DNA broke tolerance against mouse gp75, possibly by providing help from CD4(+) T cells. Mechanisms required for tumor protection were not necessary for autoimmunity, demonstrating that tumor immunity can be uncoupled from autoimmune manifestations.

The role of endoscopic extraperitoneal herniorrhaphy: where do we stand in 2005?

Inguinal hernia repair is a common surgical procedure, but the most effective surgical technique remains controversial. The evolution of laparoscopic techniques has allowed reproduction of open preperitoneal repair via an endoscopic total extraperitoneal (TEP) approach. More recently, the advent of comprehensive training in laparoscopy has allowed TEP to continue evolving as the feasibility of this approach gains recognition as a preferable technique. Once considered very difficult to learn, TEP currently is adequately taught in many surgical training programs. This report reviews the fundamentals and details various modifications that make this procedure more desirable than open procedures and other laparoscopic techniques. A resultant decrease in operative time, cost of the procedure, and morbidity to the patient is routine. In addition, the authors review their institutional experience and examine other current evidence-based data.

Intraperitoneal immunotherapy: historical perspectives and modern therapy.

Intraperitoneal immunotherapy represents a novel strategy for the management of peritoneal metastases (PM). Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has remained the gold standard of treatment for patients with PM, yet despite optimal treatment, recurrence rates remain high and long-term survival poor. From Coley's toxins to immune checkpoint inhibitors, the wide variety of anticancer immunotherapeutic strategies are now garnering attention for control of regional disease of the peritoneal cavity. Early studies with vaccine-based therapies, adoptive cell transfer, immune checkpoint inhibitors, and chimeric T cells with tumor-specific antigen receptors (CAR-T cells) are being performed, showing promise for control of peritoneal spread and induction of lasting anticancer immunity. In addition, catumaxomab, a trifunctional antibody, has been approved for intraperitoneal immunotherapy in Europe for the control of malignant ascites in patients with epithelial cell adhesion molecule positive cancers. We review a brief history of immunotherapy and current modalities under investigation for intraperitoneal use in the treatment of PM.

Alternative roles for interferon-gamma in the immune response to DNA vaccines encoding related melanosomal antigens.

Tyrosinase-related proteins-1 and -2 (gp75/TRP-1 and TRP-2) are melanosomal membrane glycoproteins recognized by antibodies and T-cells from patients with melanoma. Xenogeneic DNA immunization against gp75/TRP-1 generates antibody-dependent tumor immunity and autoimmune depigmentation. In contrast xenogeneic TRP-2 DNA immunization induces immunity mediated by CD8+ T-cells. The role of IFN-gamma in the generation of tumor immunity and autoimmune depigmentation in these two models was investigated. No tumor protection and minimal depigmentation was observed after immunization with human TRP-2 DNA in mice deficient in IFN-gamma ligand. Repletion with recombinant murine IFN-gamma restored tumor immunity. Experiments using IL4 deficient mice demonstrated that tumor immunity was unaffected but that autoimmune depigmentation was potentially accelerated, consistent with down-modulation of autoimmunity against TRP-2 by IL4. In contrast, IFN-gamma was not required for the generation of immunity to gp75/TRP-1. In fact, exogenous IFN-gamma ablated autoantibody responses against gp75/TRP-1 after xenogeneic DNA immunization, consistent with a down-regulatory effect of IFN-gamma. These results show that immunity to TRP-2 following DNA immunization uses an IFN-gamma-dependent Th1 pathway, but immunity to gp75/TRP-1 is down-regulated by IFN-gamma.

Immunization with DNA coding for gp100 results in CD4 T-cell independent antitumor immunity.

BACKGROUND: Xenogeneic DNA immunization can exploit small differences in expressed protein sequence resulting in immune recognition of self-molecules. We hypothesized that immunizing mice with xenogeneic DNA coding for the human melanosomal membrane glycoprotein gp100 would overcome immune ignorance or tolerance and result in tumor immunity. We also investigated the immunologic mechanisms of the antitumor immunity. METHODS: C57BL/6 mice were immunized with DNA coding for human gp100, mouse gp100, or control vector by gene gun. After immunization, mice were challenged with a syngeneic melanoma expressing gp100, and tumor growth was analyzed. Mice deficient in major histocompatibility complex class I or class II molecules were similarly studied to assess the immunologic mechanism of the tumor protection. RESULTS: There was significant tumor protection after vaccination with xenogeneic human gp100 DNA. Class I, but not class II, major histocompatibility complex molecules were required for tumor immunity. In addition, mice immunized with human gp100 demonstrated autoimmunity manifested as coat color depigmentation. CONCLUSIONS: Immunization with xenogeneic DNA coding for the melanosomal glycoprotein gp100 results in tumor protection and autoimmune depigmentation. These results show that xenogeneic DNA vaccines can lead to cancer immunity without CD4(+) T-cell help with potential implications for rational vaccine design.

Soft tissue sarcomas of the groin: diagnosis, management, and prognosis.

BACKGROUND: Sott tissue sarcomas (STS) of the groin may present a difficult problem because or misdiagnosis as groin hernia and proximity to major neurovascular structures. We evaluated our management and survival in a large cohort of patients. STUDY DESIGN: Patients treated between July 1, 1982 and July 1, 1998 with primary or recurrent STS of the groin were included. Groin sarcomas were defined as those tumors within 5 cm of the inguinal crease. Patient, tumor, clinical, and survival data were analyzed using a log rank test and Cox regression. RESULTS: We treated and followed 88 patients with STS of the groin. The median age was 52 years (range 16 to 86 years) and 55 patients (63%) were male. Disease-specific survival was 72% at 5 years. Tumors tended to be larger than 5 cm (52%), deep (72%), and high-grade (60%). Unfavorable prognostic factors for disease-specific survival were high grade (p < 0.001), neurovascular invasion (p < 0.001), positive margin (p < 0.01), deep depth (p < 0.01), and selection for adjuvant therapy (p < 0.005). Multivariate analysis indicated age greater than 50 years (p < 0.05), high grade (p < 0.001), neurovascular invasion (p < 0.001), and positive microscopic margins (p < 0.001). Fourteen patients (16%) were diagnosed with STS at hernia operation then went on to a definitive operation with no impact on survival. Seventeen patients (19%) had involvement of a major vessel or nerve, and 5 of these ultimately required amputations, 3 for local recurrence. CONCLUSIONS: High grade, neurovascular invasion, and positive microscopic margins are associated with poor outcomes. The biology of these tumors is similar to other extremity STS, and similar principles of management apply. Even with neurovascular involvement, most patients with primary groin STS do not require amputation.

Immunotherapeutic approach to cancer with cutaneous DNA vaccination.

Innovations for the development of cancer vaccines are emerging from advances in molecular immunology and cancer biology (1). Of these, DNA-based vaccination has become a powerful and potentially versatile method for eliciting an immune response against cancer. One method for DNA immunization involves the delivery of plasmid DNA by particle bombardment. Originally developed for plant hybridization, this approach has proven to be readily transferable to mammalian applications (2-3). Otherwise known as the gene gun, this method allows for the introduction of exogenous "naked" DNA into skin (4) (Fig. 1). Fig. 1. Photograph of the helium-driven gene gun. This is a hand-held device attached to a high pressure helium line and electrical source which operates the trigger. As shown, plastic bullets containing gold particles coated with plasmid DNA are measured and cut to fit within a cartridge. The cartridge, filled with 12 bullets, is easily placed within the barrel of the gun.

Immunotherapeutic approaches to sarcoma.

In the last decade, the most important factor in the rekindled interest in immune therapy for cancer is the development of new methods to identify tumor antigens that can be recognized by T-cells and other immune effectors. In addition, greater knowledge about tolerance and mechanisms of tumor cell evasion from immune effectors has made the prospect of developing clinically effective immune therapies for cancer seem promising. Research in immune therapies for sarcoma has been limited, mainly because of the previous lack of defined tumor antigens in this disease and the low prevalence of sarcoma in the general population. We will review the fundamental concepts of tumor immunobiology, both cellular and humoral, and highlight the new, powerful methods for identifying novel tumor antigens. Further, we will focus on the unique situation presented by sarcoma as the only solid tumor in which many cytogenetic abnormalities have been characterized which encode for unique, tumor-specific fusion proteins that are ideal targets for immune-based therapy. We will review the specifics of vaccine therapy approach to this disease, with emphasis on strategies to improve the immunogenicity of newly defined tumor antigens in sarcoma.

Dermatofibrosarcoma protuberans: A clinicopathologic analysis of patients treated and followed at a single institution.

BACKGROUND: Despite optimal surgical therapy for patients with dermatofibrosarcoma protuberans (DFSP), some patients still continue to develop local recurrence. The authors' objective was to identify and analyze clinicopathologic factors for disease free survival in a large group of patients who were followed prospectively at a single institution. METHODS: Prospectively collected data and pathology slides were available for review from 159 patients with primary or recurrent DFSP who underwent treatment between July 1950 and July 1998. The study group was comprised of patients with either the "classic" form of DFSP or the fibrosarcomatous "high grade" variant of DFSP (FS-DFSP). Patient, tumor, pathologic, and treatment factors were analyzed using the log rank test for univariate influence and Cox regression analysis for multivariate influence. Local recurrence free survival was determined by the Kaplan-Meier actuarial method. RESULTS: Of the 159 patients who comprised the current study group, 134 (84%) had the classic form of DFSP. The FS-DFSP variant was found in the remaining 25 patients (16%). The overall 5-year local recurrence free survival rate was 75%, with a median follow-up of 4. 75 years. The 5-year recurrence free survival rate for each group was 81% and 28%, respectively. On univariate analysis, age > 50 years, very close (< 1 mm) to positive microscopic margins, FS-DFSP variant, high mitotic rate, and increased cellularity were unfavorable prognostic factors. Multivariate analysis determined very close (< 1 mm) to positive microscopic margins and FS-DFSP variant to be independent adverse prognostic factors. For the 34 patients who developed a recurrence after surgical resection (21%), the median time to local recurrence was 32 months. Of the patients in this group, two died from metastatic disease. CONCLUSIONS: The prognosis after surgical resection with negative and sometimes positive microscopic margins for patients with DFSP is very good. However, increased age, high mitotic index, and increased cellularity are predictors of poor clinical outcome. The FS-DFSP variant represents a much more aggressive tumor with metastatic potential. Patients who are treated with curative intent for FS-DFSP should undergo aggressive attempts at complete surgical resection. Patients with recurrent classic DFSP without evidence of adverse prognostic features may benefit from conservative management, especially in the setting of potentially unresectable disease.

The management of unicentric and multicentric Castleman's disease: a report of 16 cases and a review of the literature.

BACKGROUND: Castleman's disease (CD), or angiofollicular lymph node hyperplasia, creates both diagnostic and therapeutic dilemmas for most physicians. For patients with this rare and poorly understood disease, the optimal therapy is unknown. The authors report their experience during the years 1986-1997 with this uncommon clinicopathologic entity. METHODS: Sixteen patients with a histologic diagnosis of CD were identified in the pathology database. Unicentric disease was defined as a solitary mass. Multicentric disease compromised patients with widespread lymphadenectomy. Clinical, radiologic, and laboratory data were analyzed to evaluate treatment response. RESULTS: The study group consisted of 16 patients classified into 3 clinicopathologic groups: hyaline-vascular, plasma cell, and "mixed." Of those patients who underwent complete surgical excision of a unicentric hyaline-vascular CD mass (n = 8), all remain symptom free without clinical or radiographic recurrence. Two patients remain asymptomatic following partial resection or radiation therapy for an unresectable unicentric hyaline-vascular CD mass. Two patients with multicentric hyaline-vascular CD are currently in complete remission following adjuvant therapy. Multicentric plasma cell CD was present in a single patient. This patient (who underwent surgical and systemic therapy) died of disease within 4 months of presentation. Three patients with unicentric hyaline-vascular/plasma cell-CD remain symptom free following either complete resection or observation. CONCLUSIONS: The authors recommend surgical resection for patients with the unicentric variant of CD. Surgical removal of a unicentric mass of hyaline-vascular or hyaline-vascular/plasma cell type is curative. Partial resection, radiotherapy, or observation alone may avoid the need for excessively aggressive therapy. Patients with multicentric disease, either hyaline-vascular or plasma cell type, do not benefit from surgical management and should be candidates for multimodality therapy, the nature of which has yet to be defined.

Adenovirus-mediated expression of melanoma antigen gp75 as immunotherapy for metastatic melanoma.

Melanocyte differentiation antigens, such as the brown locus protein gp75, are potential biological targets for immunotherapy. We investigated whether expression of the murine gp75 cDNA mediated by an adenovirus (Ad) vector could induce melanoma rejection using this model self antigen that usually induces tolerance, and whether Ad vector-directed production of interleukin-2 (IL2) might augment this response. To evaluate this approach, Ad vectors were constructed containing the murine gp75 cDNA (Ad.gp75) and the human IL2 cDNA (Ad.IL2). Efficacy was evaluated in C57BI/6 mice challenged i.v. with 10(5) B16 cells, using the number of lung metastases as the efficacy parameter. Naive control mice developed 175 +/- 12 metastases by day 14. Controls receiving intranasal Ad.IL2 1 day after B16 cell injection, intraperitoneal (i.p.) mitomycin-C-treated B16 cells +/- i.p. Ad.IL2 before B16 cell challenge and Ad.beta gal-treated mice had similar numbers of metastases as controls (P > 0.1). In marked contrast, preimmunization with intradermal Ad.gp75 provided dramatic reduction in the number of lung metastases (52 +/- 7, 29% of control). Addition of regional (intranasal delivery to the lung) Ad.IL2 to intradermal Ad.gp75 preimmunization 1 day following tumor challenge provided further protection (18 +/- 6, 10% of control). Depletion of CD4+ and CD8+ T-cell subsets effectively blocked the protective effect seen following immunization. Adoptive transfer of macrophage-depleted splenocytes from Ad.gp75-immunized mice similarly afforded significant protection against B16 tumor cell challenge. Further, serum obtained 21 days following Ad.gp75 immunization showed no detectable anti-gp75 antibody by immunoprecipitation. These results suggest that immunization with Ad.gp75 induces cellular immune responses that are capable of rejecting B16 melanoma in a host that is usually tolerant to gp75 antigen.

Injection of DNA encoding granulocyte-macrophage colony-stimulating factor recruits dendritic cells for immune adjuvant effects.

An important issue for effective vaccines is the development of potent adjuvants that can facilitate induction or augmentation of immunity. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a growth factor for myeloid progenitors of monocytes and dendritic cells (DC), which upon maturation are antigen-presenting cells (APC). The adjuvant effects of inoculation of DNA encoding GM-CSF into skin were studied. Initial experiments examined whether the GM-CSF gene injected into the skin of mice could affect the density of epidermal DC (Langerhans cells). DNA encoding GM-CSF delivered by particle bombardment into skin resulted in a significant increase of epidermal DC at the inoculation site. Kinetic analysis of epidermal recruitment after GM-CSF inoculation showed an increase in DC that peaked at seven days. This increase was accompanied by recruitment of DC into draining lymph nodes. The adjuvant effects of DNA encoding GM-CSF inoculated into skin were measured by the ability to augment antibody and T-cell responses against poorly immunogenic tumor antigens. Peptide immunization at skin sites containing epidermal DC newly recruited by GM-CSF DNA elicited T-cell responses against mutant p53, whereas peptide immunization of control skin sites did not elicit any detectable T-cell responses. Likewise, generation of antibodies following immunization with DNA encoding human gp75TRP1, a tyrosinase family member expressed by melanomas, was accelerated and protection from tumor challenge augmented by GM-CSF DNA.