A phase I study of interleukin 12 with trastuzumab in patients with human epidermal growth factor receptor-2-overexpressing malignancies: analysis of sustained interferon gamma production in a subset of patients

PURPOSE

On the basis of preclinical studies, we hypothesized that interleukin (IL)12 would potentiate the antitumor actions of an antihuman epidermal growth factor receptor-2 (HER2) monoclonal antibody (trastuzumab). We conducted a Phase I trial to determine the safety and optimal biological dose of IL-12 when given in combination with trastuzumab.

PATIENTS AND METHODS

Patients with metastatic HER2-positive malignancies received trastuzumab on day 1 of each weekly cycle. Beginning in week 3, patients also received intravenous injections of IL-12 on days 2 and 5. The IL-12 component was dose-escalated within cohorts of 3 patients (30, 100, 300, or 500 ng/kg). Correlative assays were conducted using serum samples and peripheral blood cells obtained during the course of therapy.

RESULTS

Fifteen patients were treated, including 12 with HER2 2+ or 3+ breast cancer. The regimen was well tolerated with IL-12-induced grade 1 nausea and grade 2 fatigue predominating. Evaluation of dose-limiting toxicity and biological end points suggested that the 300 ng/kg dose was both the maximally tolerated dose and the optimal biological dose of IL-12 for use in combination with trastuzumab. Two patients with HER2 3+ breast cancer within the 500 ng/kg dose level experienced grade 1 asymptomatic decreases in left ventricular ejection fraction of 12% and 19% after 3 and 10 months of therapy, respectively. There was one complete response in a patient with HER2 3+ breast cancer metastatic to the axillary, mediastinal, and supraclavicular nodes, and 2 patients with stabilization of bone disease lasting 10 months and >12 months, respectively. Correlative assays showed sustained production of interferon (IFN)gamma by natural killer cells only in those patients experiencing a clinical response or stabilization of disease. Elevated serum levels of macrophage inflammatory protein-1alpha, tumor necrosis factor-alpha, and the antiangiogenic factors IFN-gamma inducible protein-10 and monokine induced by gamma were also observed in these patients. Patient genotyping suggested that a specific IFN-gamma gene polymorphism might have been associated with increased IFN-gamma production. The ability of patient peripheral blood cells to conduct antibody-dependent cellular cytotoxicity against tumor targets in vitro did not correlate with clinical response or dose of IL-12.

CONCLUSIONS

The addition of IL-12 to trastuzumab therapy did not appear to enhance the efficacy of this antibody treatment. Sustained production of IFN-gamma and other cytokines were observed in three patients: One who exhibited a complete response and two others who had stabilization of disease lasting over 6 months. Given the small sample size and heterogeneity of the patient population, the effects of IL-12 on the innate immune response to trastuzumab therapy should be further explored in the context of a larger clinical trial.

The antitumor effects of IFN-alpha are abrogated in a STAT1-deficient mouse

IFN-alpha activates the signal transducer and activator of transcription (STAT) family of proteins; however, it is unknown whether IFN-alpha exerts its antitumor actions primarily through a direct effect on malignant cells or by stimulating the immune system. To investigate the contribution of STAT1 signaling within the tumor, we generated a STAT1-deficient melanoma cell line, AGS-1. We reconstituted STAT1 into AGS-1 cells by retroviral gene transfer. The resulting cell line (AGS-1STAT1) showed normal regulation of IFN-alpha-stimulated genes (e.g., H2k, ISG-54) as compared with AGS-1 cells infected with the empty vector (AGS-1MSCV). However, mice challenged with the AGS-1, AGS-1STAT1, and AGS-1MSCV cell lines exhibited nearly identical survival in response to IFN-alpha treatment, indicating that restored STAT1 signaling within the tumor did not augment the antitumor activity of IFN-alpha. In contrast, STAT1-/- mice could not utilize exogenous IFN-alpha to inhibit the growth of STAT1+/+ melanoma cells in either an intraperitoneal tumor model or in the adjuvant setting. The survival of tumor-bearing STAT1-/- mice was identical regardless of treatment (IFN-alpha or PBS). Additional cell depletion studies demonstrated that NK cells mediated the antitumor effects of IFN-alpha. Thus, STAT1-mediated gene regulation within immune effectors was necessary for mediating the antitumor effects of IFN-alpha in this experimental system.

Patterns of recurrence after sentinel lymph node biopsy for breast cancer

BACKGROUND

Sentinel lymph node biopsy (SLNB) is gaining acceptance as an alternative to axillary lymph node dissection. The purpose of this study was to determine the frequency and pattern of disease recurrence after SLNB.

METHODS

Two-hundred twenty-two consecutive patients undergoing SLNB from April 6, 1998, to October 27, 1999, and who were >or=24 months out from their procedure were identified from a prospectively maintained database. Retrospective chart review and data analysis were performed to identify variables predictive of recurrence.

RESULTS

The median patient follow-up was 32 months (range, 24-43 months). A total of 159 patients (72%) were sentinel lymph node (SLN) negative and had no further axillary treatment. Five of these patients (3.1%) developed a recurrence (one local and four distant), with no isolated regional (axillary) recurrences. Sixty-three patients (28%) were SLN positive and underwent a subsequent axillary lymph node dissection. Six of these patients (9.5%) developed a recurrence (three local, one regional, and two distant). Pathologic tumor size (P <.001), lymphovascular invasion (P =.018), and a positive SLN (P =.048) were all statistically significantly associated with disease recurrence.

CONCLUSIONS

With a minimum follow-up of 24 months, patients with a negative SLN and no subsequent axillary treatment demonstrate a low frequency of disease recurrence. This supports the use of SLNB as the sole axillary staging procedure in SLN-negative patients.

A chimeric multi-human epidermal growth factor receptor-2 B cell epitope peptide vaccine mediates superior antitumor responses

Immunotherapeutic approaches to cancer should focus on novel undertakings that modulate immune responses by synergistic enhancement of antitumor immunological parameters. Cancer vaccines should preferably be composed of multiple defined tumor Ag-specific B and T cell epitopes. To develop a multiepitope vaccine, 12 high ranking B cell epitopes were identified from the extracellular domain of the human epidermal growth factor receptor-2 (HER-2) oncoprotein by computer-aided analysis. Four novel HER-2 B cell epitopes were synthesized as chimeras with a promiscuous T cell epitope (aa 288-302) from the measles virus fusion protein (MVF). Two chimeric peptide vaccines, MVF HER-2(316-339) and MVF HER-2(485-503) induced high levels of Abs in outbred rabbits, which inhibited tumor cell growth. In addition, Abs induced by a combination of two vaccines, MVF HER-2(316-339) and MVF HER-2(628-647) down-modulated receptor expression and activated IFN-gamma release better than the individual vaccines. Furthermore, this multiepitope vaccine in combination with IL-12 caused a significant reduction (p = 0.004) in the number of pulmonary metastases induced by challenge with syngeneic tumor cells overexpressing HER-2. Peptide Abs targeting specific sites in the extracellular domain may be used for exploring the oncoprotein's functions. The multiepitope vaccine may have potential application in the treatment of HER-2-associated cancers.

Intra-arterial administration of TNF-alpha followed by arterial ablation is an effective therapy for a regionally confined TNF-resistant rat mammary adenocarcinoma

Tumor necrosis factor-alpha (TNF-alpha) is an immunomodulatory cytokine that has exhibited anti-tumor activity in a variety of experimental systems. However, the toxicities associated with systemic administration of TNF-alpha have limited its clinical utility and have led to the investigation of targeted delivery techniques with the ability to present the TNF-alpha dose directly to the vascular bed of the tumor. The intra-arterial (IA) administration of TNF-alpha to patients with liver metastases represents one such approach, and recent work suggests that subsequent ablation of the tumor's arterial supply via embolization may enhance the efficacy of intra-arterial treatments (hepatic chemoembolization). The present study was undertaken to test the hypothesis that IA administration of TNF-alpha is superior to the intravenous (IV) route for inhibition of tumor growth in a regionally confined rat mammary adenocarcinoma model that provides for ablation of the arterial supply to the tumor following cytokine therapy. Rats bearing hind limb mammary adenocarcinomas received single IA or IV infusions of 8 x 10(5), 1 x 10(6), and 1.5 x 10(6) units of TNF-alpha via the common femoral artery (CFA) followed 1 h later by ligation of the artery. Control animals received either no treatment or IA infusion of 2% normal rat serum (NRS) followed by ipsilateral CFA ligation. Tumor size was measured every other day after treatment. Tumor growth inhibition occurred in the first 5 to 10 days after treatment. IV administration of TNF-alpha did not result in visual tumor necrosis or significant reduction in the rate of tumor growth. IA administration of TNF-alpha resulted in statistically significant diminution of tumor size as compared to untreated controls and animals receiving IA 2% normal rat serum (NRS; P<0.05 at days 6, 8 and 10), regardless of the dose employed. The maximum growth inhibition with IA TNF-alpha was a 91% reduction in tumor volume that was achieved with a dose of 1 x 10(6) U TNF-alpha. These results demonstrate improved anti-tumor activity with the IA administration of TNF-alpha over the IV route in a regionally confined mammary adenocarcinoma. IA administration of biologic response modifiers like TNF-alpha may therefore be a useful approach for the hepatic chemoembolization of breast adenocarcinomas metastatic to the liver.

A phase I trial of escalating doses of trastuzumab combined with daily subcutaneous interleukin 2: report of cancer and leukemia group B 9661

PURPOSE

The purpose of this study was to determine the toxicity of escalating doses of trastuzumab when combined with a fixed dose regimen of interleukin (IL)-2.

EXPERIMENTAL DESIGN

Eligible patients had nonhematological malignancies for which standard therapy did not exist or was no longer effective and had tumors that overexpressed HER2. IL-2 was initially administered at a dose of 1.25 million IU/m(2) (low dose) s.c. daily except for 3 days every 2 weeks, when it was given at a dose of 15 million IU/m(2) (intermediate dose). These doses were reduced to 1.0 million and 12 million IU/m(2) after the first 18 patients. Trastuzumab was administered i.v. just before the first intermediate IL-2 dose and was escalated in cohorts of six or more patients from 1 mg/kg every 2 weeks to 8 mg/kg weekly. In vitro cytotoxicity testing was performed with patient peripheral blood mononuclear cells and HER2-overexpressing cell lines.

RESULTS

Forty-five patients were treated. Dose-related toxicity from trastuzumab was not observed. IL-2-related toxicities such as fever, chills, and fatigue were less common with the reduced doses of IL-2. There were two grade 3 and three grade 4 pulmonary reactions. Four major responses were observed, all in breast cancer patients treated with trastuzumab doses of at least 4.0 mg/kg. Although IL-2 produced expansion of natural killer cell subsets, there was no correlation between in vitro cytotoxicity and clinical response.

CONCLUSIONS

A regimen of IL-2 combined with trastuzumab is feasible, and response numbers are encouraging. Further testing of this regimen is warranted if the pulmonary toxicity can be ameliorated.

IL-12 enhances the natural killer cell cytokine response to Ab-coated tumor cells

The anti-tumor activity of recombinant mAb's directed against tumor cell growth receptors has generally been considered to result from direct antiproliferative effects, the induction of apoptosis, or possibly Ab-dependent cellular cytotoxicity mediated against tumor targets. However, it remains unclear to what degree these mechanisms actually aid in the clearance of Ab-coated tumor cells in vivo. We show here that NK cells secrete a distinct profile of potent immunostimulatory cytokines in response to dual stimulation with Ab-coated tumor cells and IL-12. This response could not be duplicated by costimulation with other ILs and was significantly enhanced in the presence of monocytes. Cytokine production was dependent upon synergistic signals mediated by the activating receptor for the Fc portion of IgG (FcgammaRIII) and the IL-12 receptor expressed on NK cells. Coadministration of Ab-coated tumor cells and IL-12 to BALB/c mice resulted in enhanced circulating levels of NK cell-derived cytokines with the capacity to augment anti-tumor immunity. These findings suggest that, in addition to mediating cellular cytotoxicity and apoptosis, the anti-tumor activity of mAb's might also result from activation of a potent cytokine secretion program within immune effectors capable of recognizing mAb-coated targets.

IL-12 enhances the natural killer cell cytokine response to Ab-coated tumor cells

The anti-tumor activity of recombinant mAb's directed against tumor cell growth receptors has generally been considered to result from direct antiproliferative effects, the induction of apoptosis, or possibly Ab-dependent cellular cytotoxicity mediated against tumor targets. However, it remains unclear to what degree these mechanisms actually aid in the clearance of Ab-coated tumor cells in vivo. We show here that NK cells secrete a distinct profile of potent immunostimulatory cytokines in response to dual stimulation with Ab-coated tumor cells and IL-12. This response could not be duplicated by costimulation with other ILs and was significantly enhanced in the presence of monocytes. Cytokine production was dependent upon synergistic signals mediated by the activating receptor for the Fc portion of IgG (FcgammaRIII) and the IL-12 receptor expressed on NK cells. Coadministration of Ab-coated tumor cells and IL-12 to BALB/c mice resulted in enhanced circulating levels of NK cell-derived cytokines with the capacity to augment anti-tumor immunity. These findings suggest that, in addition to mediating cellular cytotoxicity and apoptosis, the anti-tumor activity of mAb's might also result from activation of a potent cytokine secretion program within immune effectors capable of recognizing mAb-coated targets.

Interleukin-2 enhances the natural killer cell response to Herceptin-coated Her2/neu-positive breast cancer cells

The Her2/neu (c-erbB-2) oncogene encodes a 185-kDa protein tyrosine kinase which is overexpressed in 20% of breast adenocarcinomas and is recognized by a humanized anti-Her2/neu monoclonal antibody (mAb) (rhu4D5 or Herceptin). Natural killer (NK) cells are capable of mediating antibody-dependent cell cytotoxicity (ADCC) against antibody-coated targets via their expression of a low-affinity receptor for IgG (FcgammaRIII or CD16). NK cells can be expanded in cancer patients via the administration of low-dose interleukin-2 (IL-2) and become potent cytotoxic effectors following exposure to high doses of IL-2. We tested IL-2-activated NK cells against Her2/neu+ (MCF-7Her2/neu) and Her2/neu- (MDA-468) breast cancer cell lines in a 4-h 51Cr-release cytotoxicity assay in the presence or absence of rhu4D5 mAb (effector : target ratio = 10 : 1). Specific lysis of rhu4D5-coated MCF-7Her2/neu and MDA-468 target cells by IL-2-activated NK cells was 35% and 3%, respectively (p < 0.05). Lysis was less than 5% when targets were treated with either the non-humanized mu4D5 mAb or control huIgG. Lysis of rhu4D5-coated MCF-7Her2/neu cells was inhibited by 80 % when NK cells were pre-treated with an anti-Fc receptor antibody prior to use in the cytotoxicity assay. Enhanced ADCC of MCF-7Her2/neu target cells was seen when the effector cells consisted of mononuclear cells obtained from a patient demonstrating significant expansion of NK cells secondary to therapy with low-dose IL-2. Serum from patients receiving infusions of rhu4D5 mAb could substitute for exogenous antibody in the ADCC assay. NK cells activated by rhu4D5-coated tumor cells in the presence of IL-2 also produced large amounts of IFN-gamma with concomitant up-regulation of cell-surface activation markers CD25 and CD69. These results lend support to the concurrent use of rhu4D5 mAb and IL-2 therapy in patients with cancers that express the Her2/neu oncogene.

Human natural killer cells: a unique innate immunoregulatory role for the CD56(bright) subset

During the innate immune response to infection, monocyte-derived cytokines (monokines), stimulate natural killer (NK) cells to produce immunoregulatory cytokines that are important to the host's early defense. Human NK cell subsets can be distinguished by CD56 surface density expression (ie, CD56(bright) and CD56(dim)). In this report, it is shown that CD56(bright) NK cells produce significantly greater levels of interferon-gamma, tumor necrosis factor-beta, granulocyte macrophage-colony-stimulating factor, IL-10, and IL-13 protein in response to monokine stimulation than do CD56(dim) NK cells, which produce negligible amounts of these cytokines. Further, qualitative differences in CD56(bright) NK-derived cytokines are shown to be dependent on the specific monokines present. For example, the monokine IL-15 appears to be required for type 2 cytokine production by CD56(bright) NK cells. It is proposed that human CD56(bright) NK cells have a unique functional role in the innate immune response as the primary source of NK cell-derived immunoregulatory cytokines, regulated in part by differential monokine production.

Coadministration of interleukin-18 and interleukin-12 induces a fatal inflammatory response in mice: critical role of natural killer cell interferon-gamma production and STAT-mediated signal transduction

The administration of therapeutic doses of recombinant cytokines to patients with malignant disease can be complicated by systemic toxicities, which in their most severe form may present as a systemic inflammatory response. The combination of interleukin (IL)-18 and IL-12 has synergistic antitumor activity in vivo yet has been associated with significant toxicity. The effects of IL-18 plus IL-12 were examined in a murine model, and it was found that the daily, simultaneous administration of IL-18 and IL-12 resulted in systemic inflammation and 100% mortality within 4 to 8 days depending on the strain employed. Mice treated with IL-18 plus IL-12 exhibited unique pathologic findings as well as elevated serum levels of proinflammatory cytokines and acute-phase reactants. The actions of tumor necrosis factor-alpha did not contribute to the observed toxicity, nor did T or B cells. However, toxicity and death from treatment with IL-18 plus IL-12 could be completely abrogated by elimination of natural killer (NK) cells or macrophages. Subsequent studies in genetically altered mice revealed that NK-cell interferon-gamma mediated the fatal toxicity via the signal transducer and activator of transcription pathway of signal transduction. These data may provide insights into methods of ameliorating cytokine-induced shock in humans. (Blood. 2000;96:1465-1473)

A fatal cytokine-induced systemic inflammatory response reveals a critical role for NK cells

The mechanism of cytokine-induced shock remains poorly understood. The combination of IL-2 and IL-12 has synergistic antitumor activity in vivo, yet has been associated with significant toxicity. We examined the effects of IL-2 plus IL-12 in a murine model and found that the daily, simultaneous administration of IL-2 and IL-12 resulted in shock and 100% mortality within 4 to 12 days depending on the strain employed. Mice treated with IL-2 plus IL-12 exhibited NK cell apoptosis, pulmonary edema, degenerative lesions of the gastrointestinal tract, and elevated serum levels of proinflammatory cytokines and acute phase reactants. The actions of TNF-alpha, IFN-gamma, macrophage-inflammatory protein-1alpha, IL-1, IL-1-converting enzyme, Fas, perforin, inducible nitric oxide synthase, and STAT1 did not contribute to the observed toxicity, nor did B or T cells. However, toxicity and death from treatment with IL-2 plus IL-12 could be completely abrogated by elimination of NK cells. These results suggest that the fatal systemic inflammatory response induced by this cytokine treatment is critically dependent upon NK cells, but does not appear to be mediated by the known effector molecules of this cellular compartment. These data may provide insight into the pathogenesis of cytokine-induced shock in humans.

A Fatal Cytokine-Induced Systemic Inflammatory Response Reveals a Critical Role for NK Cells

The mechanism of cytokine-induced shock remains poorly understood. The combination of IL-2 and IL-12 has synergistic antitumor activity in vivo, yet has been associated with significant toxicity. We examined the effects of IL-2 plus IL-12 in a murine model and found that the daily, simultaneous administration of IL-2 and IL-12 resulted in shock and 100% mortality within 4 to 12 days depending on the strain employed. Mice treated with IL-2 plus IL-12 exhibited NK cell apoptosis, pulmonary edema, degenerative lesions of the gastrointestinal tract, and elevated serum levels of proinflammatory cytokines and acute phase reactants. The actions of TNF-α, IFN-γ, macrophage-inflammatory protein-1α, IL-1, IL-1-converting enzyme, Fas, perforin, inducible nitric oxide synthase, and STAT1 did not contribute to the observed toxicity, nor did B or T cells. However, toxicity and death from treatment with IL-2 plus IL-12 could be completely abrogated by elimination of NK cells. These results suggest that the fatal systemic inflammatory response induced by this cytokine treatment is critically dependent upon NK cells, but does not appear to be mediated by the known effector molecules of this cellular compartment. These data may provide insight into the pathogenesis of cytokine-induced shock in humans.

Flt3 ligand promotes the generation of a distinct CD34(+) human natural killer cell progenitor that responds to interleukin-15

Interleukin-15 (IL-15) is produced by human bone marrow (BM) stromal cells and can induce CD34(+) hematopoietic progenitor cells (HPCs) to differentiate into CD56(+)CD3(-) natural killer (NK) cells in the absence of stromal cells. IL-15 mediates its effects by signaling through the beta and gammac chains of the IL-2/15 receptor (R). The c-kit ligand (KL), also produced by stromal cells, enhances the expansion of NK cells from CD34(+) HPCs in the presence of IL-15, but alone has no ability to differentiate NK cells. Mice deficient in KL do not appear to have a quantitative deficiency in NK cells, suggesting that other stromal cell factors may contribute to NK cell expansion. Flt3 ligand (FL) is also produced by BM stromal cells and has homology with KL. Furthermore, mice with a targeted disruption of the FL gene have reduced numbers of NK cells. We evaluated here the effects of FL on human NK cell development and expansion from CD34(+) HPCs. Like KL, FL significantly enhanced the expansion of NK cells from CD34(+) HPCs in the presence of IL-15, compared with IL-15 alone. However, FL alone had no effect on NK cell differentiation. We therefore explored the mechanism by which FL promotes IL-15-mediated NK cell development. FL was found to induce IL-2/15Rbeta (CD122) expression on CD34(bright) HPCs. The CD34(bright) CD122(+) cell coexpressed CD38, but lacked expression of CD7, CD56, NK cell receptors (NKRs), or cytotoxic activity in the absence of IL-15. Using limiting dilution analysis in the presence of IL-15 alone, we demonstrated that the FL-induced CD34(bright)CD122(+) HPCs had an NK cell precursor frequency 20- to 60-fold higher than the CD34(dim/neg)CD122(-) HPCs and 65- to 235-fold higher than fresh CD34(+) HPCs. KL had similar effects as FL, but induced a significantly lower percentage of CD34(bright)CD122(+) cells (P </=.01). Both FL and KL also increased IL-15R transcript in CD34(+) HPCs. Culture of CD34(+) HPCs in FL or KL, followed by culture in IL-15 alone, induced expression of both C-type lectin and Ig-superfamily NKRs on CD56(+) cells. These data collectively support a role for FL in early human NK cell development. FL or KL generate a unique CD34(bright) CD122(+)CD38(+) human NK cell intermediate from CD34(+) HPCs that lacks NK features yet is IL-15-responsive. IL-15 is then required for the induction of CD56 and NKRs, LGL morphology, cytotoxic activity, and the ability to produce abundant cytokines and chemokines.

Interferon-alpha-induced activation of signal transducer and activator of transcription proteins in malignant melanoma

IFN-alpha2b has been used to treat patients with malignant melanoma who are at high risk for recurrence after surgical resection. However, its exact mechanism of action is unknown. I hypothesized that IFN-alpha exerts a direct effect on the melanoma cell via the activation of signal transducer and activator of transcription (STAT) proteins. Cell lysates from melanoma cell lines and patient tumor samples stimulated with IFN-alpha were incubated with radiolabeled oligonucleotides representing the high affinity sis-inducible element of c-fos and the IFN stimulated response element and then analyzed for STAT activation using the electrophoretic mobility shift assay. Melanoma cell lines showed no evidence for constitutive STAT activation in the absence of cytokine stimulation but exhibited rapid activation of STAT1 and STAT2 once treated with IFN-alpha. A distinct dose-response curve was noted with maximal STAT activation occurring at approximately 10(5) units/ml IFN-alpha. Genistein, a protein tyrosine kinase inhibitor, completely suppressed IFN-alpha-induced STAT activation. Malignant melanoma tumors obtained from 17 patients exhibited dose-dependent activation of STAT1 and STAT2 in response to treatment with IFN-alpha. Pretreatment of patient melanoma tumor cells with IFN-gamma resulted in a 4 log-fold decrease in the IFN-alpha concentration required for STAT activation and promoted the increased expression of STAT1, STAT2, and p48. In summary, IFN-alpha consistently activated STAT1 and STAT2 proteins in melanoma cell lines and in melanoma tumors obtained directly from patients. This signaling pathway was dramatically sensitized to IFN-alpha by pretreatment of melanoma cells with low concentrations of IFN-gamma. These results provide molecular evidence to support the hypothesis that the clinical response to IFN-alpha may be mediated, in part, by a direct effect on the melanoma cell. These results also suggest a potential role for IFN-gamma in the treatment of malignant melanoma.

Paget's disease of the breast: a 33-year experience

BACKGROUND

Paget's disease (PD) of the breast is an uncommon condition traditionally treated with mastectomy. To assess the natural history and treatment options in PD we have reviewed the experience at the Roswell Park Cancer Institute (RPCI).

STUDY DESIGN

The medical records of patients treated for PD at RPCI between 1963 and 1996 were reviewed.

RESULTS

Eighty patients were treated in the period reviewed. The median follow up was 61 months. Sixty-eight of 80 patients had nipple changes consistent with PD including 30 who had an associated breast mass (group 1), and 38 who had no associated mass (group 2). Of the 68 patients with clinical PD, 58 (85%) were treated with mastectomy while the remainder were treated with some form of breast conserving therapy. Breast cancer (BC) was found in 56 of 68 patients (82%) with clinical PD, including 28 of 30 patients (93%) in group 1 and 28 of 38 patients (74%) in group 2. Breast cancer was centrally located (within 2 cm of the areolar margin) in 61% of patients, including 71% in group 1 and 50% in group 2. Of the 28 patients with an associated BC in group 1, 21 (75%) had invasive cancer, 6 (21%) had ductal carcinoma in situ (DCIS), and 16 (57%) had pathologic axillary nodes. Of the 28 patients with an associated BC in group 2, 10 (36%) had invasive cancer, 18 (64%) had DCIS, and 6 (21%) had positive axillary nodes. The median survival was significantly shorter for group 1 (42 months) than for group 2 (126 months; p = 0.007).

CONCLUSION

Most patients with PD have an associated BC (82%) that was centrally located (61%). In those patients without an associated mass, a significant number (26% in this series) may not have an underlying BC and may be overtreated with mastectomy. On the other hand, a significant number of patients with PD and no associated breast mass will be found to have a peripherally located tumor (29% in this series). These non-central BC masses could potentially be missed by a wide local excision that includes the areolar complex.

Stem cell factor enhances interleukin-2-mediated expansion of murine natural killer cells in vivo

The administration of low dose interleukin-2 (IL-2) results in a selective expansion of natural killer (NK) cells in vivo, and promotes the differentiation of NK cells from hematopoietic precursor cells in vitro. We have previously shown that stem cell factor (SCF ), the ligand to the c-kit tyrosine kinase receptor, enhances IL-2-induced NK cell proliferation and differentiation in vitro. Here, we investigated the effects of SCF plus IL-2 delivered to mice in vivo. Eight-week-old C57BL/6 mice were treated with a continuous subcutaneous infusion of IL-2 (1 x 10(4) IU/d) plus a daily intraperitoneal dose of SCF (100 microg/kg/d), IL-2 alone, SCF alone, or vehicle alone for 8 weeks. The in vivo serum concentration of IL-2 ranged between 352 +/- 12.0 pg/mL and 606 +/- 9.0 pg/mL, achieving selective saturation of the high affinity IL-2 receptor, while the peak SCF serum concentration was 296 +/- 13.09 ng/mL. Alone, the daily administration of SCF had no effect on the expansion of NK cells. The continuous infusion of IL-2 alone did result in a significant expansion of NK1.1+CD3- cells compared to mice treated with placebo or SCF. However, mice treated with both SCF and IL-2 showed an increase in the absolute number of NK cells that was more than twofold that seen with IL-2 alone, in the spleen (P </= .005), bone marrow (P </= .025), and blood (P < .05). NK cytotoxic activity against YAC-1 target cells was significantly higher for mice treated with SCF plus IL-2, compared to mice treated with IL-2 alone (P </= .0005). Interferon-gamma (IFN-gamma) production in cytokine-activated splenocytes was also greater for the SCF plus IL-2 group, over IL-2 treatment alone (P </= .01). The effect of SCF plus IL-2 on NK cell expansion was likely mediated via NK cell precursors, rather than mature NK cells. In summary, we provide the first evidence that SCF can significantly enhance expansion of functional NK cells induced by the prolonged administration of low dose IL-2 in vivo. Since the NK cell is a cytotoxic innate immune effector and a potent source of IFN-gamma, this therapeutic strategy for NK cell expansion may serve to further enhance innate immune surveillance against malignant transformation and infection in the setting of cancer and/or immunodeficiency.

A potential role for interleukin-15 in the regulation of human natural killer cell survival

Resting lymphocyte survival is dependent upon the expression of Bcl-2, yet the factors responsible for maintaining lymphocyte Bcl-2 protein expression in vivo are largely unknown. Natural killer (NK) cells are bone marrow-derived lymphocytes that constitutively express the beta and common gamma(c) subunits of the IL-2 receptor (R) as a heterodimer with intermediate affinity for IL-2. IL-15 also binds to IL-2Rbeta gamma(c) and is much more abundant in normal tissues than IL-2. Mice that lack the IL-2 gene have NK cells, whereas mice and humans that lack IL-2R gamma(c) do not have NK cells. Further, treatment of mice with an antibody directed against IL-2Rbeta results in a loss of the NK cell compartment. These data suggest that a cytokine other than IL-2, which binds to IL-2Rbeta gamma(c), is important for NK cell development and survival in vivo. In the current report, we show that the recently described IL-15R(alpha) subunit cooperates with IL-2Rbeta gamma(c) to transduce an intracellular signal at picomolar concentrations of IL-15. We demonstrate that resting human NK cells express IL-15R(alpha) mRNA and further, that picomolar amounts of IL-15 can sustain NK cell survival for up to 8 d in the absence of serum. NK cell survival was not sustained by other monocyte-derived factors (i.e., TNF-alpha, IL-1beta, IL-10, IL-12) nor by cytokines known to use gamma(c) for signaling (i.e., IL-4, IL-7, IL-9, IL- 13). One mechanism by which IL-15 promotes NK cell survival may involve the maintenance of Bcl-2 protein expression. Considering these functional properties of IL-15 and the fact that it is produced by bone marrow stromal cells and activated monocytes, we propose that IL-15 may function as an NK cell survival factor in vivo.

CD56bright natural killer cell subsets: characterization of distinct functional responses to interleukin-2 and the c-kit ligand

Natural killer (NK) cells are bone marrow-derived large granular lymphocytes that express the CD56 surface antigen. The CD56bright NK subset represents approximately 10% of all NK cells and is thought to be the least differentiated NK cell component in blood. The most mature NK cell expresses CD56 at low density and CD16 (FcR gammaIII) at high density, whereas CD56bright NK cells either lack CD16 (CD56bright CD16-) or express it at low density (CD56bright CD16dim). c-kit is a tyrosine kinase receptor which is expressed on both CD34+ hematopoietic precursor cells and CD56bright NK cells. In the current study, we characterize interleukin (IL)-2 receptor (IL-2R) and c-kit expression in each of the CD56bright subsets. Both the CD56bright CD16- and CD56bright CD16dim NK subsets express the high-affinity IL-2R and the c-kit receptor when isolated from fresh blood. However, each CD56bright NK cell subset has distinct functional responses to IL-2, the c-kit ligand (KL), or both. Activation of the high-affinity IL-2R on CD56bright CD16- NK cells induces a proliferative response that is significantly weaker than that observed in the CD56bright CD16dim NK cell subset. Incubation of the CD56bright CD16 NK cell subset with KL significantly enhances IL-2-induced proliferation, while KL has no such effect on the CD56bright CD16dim NK subset. Activation of the high-affinity IL-2R in both CD56bright subsets induces lymphokine-activated killer (LAK) activity, but the addition of KL has no effect on LAK activity. Co-stimulation of either CD56bright subset with IL-12 and concentrations of IL-2 that only saturate the high-affinity IL-2R induces substantial interferon (IFN)-gamma production. The addition of KL to this co-stimulatory signal enhances IFN-gamma production in both CD56bright NK subsets. The distinct functional responses to IL-2 and KL seen in the CD56bright CD16- and CD56bright CD16dim NK subsets provide insight into IL-2R signaling and suggest that each phenotype identifies a discrete stage of NK cell differentiation.

The c-kit ligand potentiates the allogeneic mixed lymphocyte reaction

The allogeneic mixed lymphocyte reaction (MLR) is a complex in vitro assay of T-cell recognition and responsiveness in which interleukin-2 (IL-2) plays a central role. We have previously demonstrated that c-kit ligand (KL) can enhance IL-2-induced proliferation in a subset of human natural killer cells expressing the c-kit tyrosine kinase receptor. In the present study, we asked whether KL could enhance IL-2-mediated T-cell proliferation in the allogeneic MLR. We demonstrate that the vast majority of activated human T-cell clones express the c-kit mRNA transcript. Binding studies performed on activated T cells with radioiodinated KL were consistent with the expression of a single class of c-kit receptors. The addition of exogenous KL to the MLR led to an increase in tritiated thymidine (3[H]-TdR) incorporation in the absence of other exogenous cytokines, and did so in a dose-dependent fashion. A reproducible increase in 3[H]-TdR incorporation was noted at concentrations of KL, which approximate those normally found in vivo. Antibody blocking of KL binding to c-kit, T-cell depletion and sorting experiments suggest that the action of KL is mediated at least in part by a direct effect on both CD4+ and CD8+ T-cells. KL's enhancement of the MLR also requires the binding of IL-2 to its high-affinity IL-2 receptor. Given the abundance of KL normally found in human serum, these data suggest that this cytokine may have a role during T-cell activation in vivo.

Receptors for interleukin (IL)-10 and IL-6-type cytokines use similar signaling mechanisms for inducing transcription through IL-6 response elements

The cytoplasmic domain of the receptor for interleukin 10 (IL-10R) contains two box 3 sequence motifs that have been identified in the signal-transducing receptor subunits for IL-6-type cytokines and noted to be required for activating STAT3 and inducing transcription through IL-6-responsive elements. To determine whether the IL-10R has signaling functions similar to IL-6R in cells normally expressing these receptors, leukocytes of the B-, T-, and NK-cell lineages were treated with either cytokine. Both cytokines activated factors that bound to the sis-inducible element and included STAT1 and STAT3. The cell response to IL-10 characteristically differed from that to IL-2/IL-15, IL-4, and interferon gamma. The signaling capabilities of the IL-10R for activating specific STAT proteins and inducing gene transcription were defined by reconstitution of receptor functions in transfected tissue culture cells. COS-1 cells, co-expressing the human IL-10R and individual STAT proteins, confirmed a preference of the IL-10R for STAT3 and STAT1. Unlike many hematopoietin receptors, the IL-10R did not detectably activate STAT5. The IL-10R, together with reporter gene constructs containing different IL-6-responsive gene elements, reconstituted in hepatoma cells an induction of transcription by IL-10 that was comparable to that by IL-6. This regulation could not be appreciably modified by enhanced expression of STAT proteins. The similar actions of IL-10R and IL-6R on the induction of endogenous IL-6-responsive genes were demonstrated in hepatoma cells stably expressing the IL-10R. These receptor functions required the presence of the box 3 motifs, as shown by the analysis of the mouse IL-10R constructs containing progressively truncated cytoplasmic domains. The data demonstrate that the IL-10R, unlike other members of the interferon receptor family, is highly effective in recruiting the signaling pathways of IL-6-type cytokine receptors.

Endogenous production of interleukin 15 by activated human monocytes is critical for optimal production of interferon-gamma by natural killer cells in vitro

Natural killer (NK) cells are large granular lymphocytes that constitutively express functional IL-2 receptors. We have shown that recombinant human IL-15 uses the IL-2 receptor to activate human NK cells and can synergize with recombinant human IL-12 to stimulate NK cell production of IFN-gamma in vitro. IFN-gamma production by NK cells is critical in the prevention of overwhelming infection by obligate intracellular microbial pathogens in several experimental animal models. Herein, we demonstrate that human monocytes produce IL-15 protein within 5 h of activation with LPS. Using an IL-15-neutralizing antiserum in a coculture of LPS-activated monocytes and NK cells, we demonstrate that monocyte-derived IL-15 is critical for optimal NK cell production of IFN-gamma. Endogenous IL-15 activates NK cells through the IL-2 receptor, and with endogenous IL-12, regulates NK cell IFN-gamma after monocyte activation by LPS. These in vitro studies are the first to characterize a function for endogenous IL-15, and as such, suggest an important role for IL-15 during the innate immune response. IL-15 may be an important ligand for the NK cell IL-2 receptor in vivo.