P5-07-04: Is a-L-Fucose Overexpressed on Cells of Aggressive Human Breast Cancers?

Enzymatic removal of a-L-fucose (fucose) was shown over 20 years ago to abolish metastases in vivo in a rat model of mammary adenocarcinoma [J Cell Biochem 1988; 37: 49–59]. Since that time, evidence has accumulated to indicate that fucose is a functional effector in human breast cancer; essential for construction of the invasive and metastatic phenotypes. In light of these findings, the role of fucose in aggressive breast cancers is worthy of further investigation.

Our group has modified the method of Wright et al. in order to selectively remove cell surface fucose from viable human breast cancer cells in vitro. In our experience, a 30 min incubation of breast cancer cells with α-L-fucosidase (3.2.1.51) leads to a loss of transformative abilities including decreased cancer cell adhesion to select extracellular matrix components, decreased invasion into complex extracellular matrices, decreased binding by relevant antibodies and lectins, and decreased adhesion of cells (rolling) to model endothelium under shear stress flow conditions.

From this work we postulated that decisive differences in phenotypic and functional properties between treated and control human breast cancer cells should be obtainable with currently available models of aggressive disease. To that end, we and others have subsequently shown that human breast cancer cells express cell surface CD44 which carries fucosylated ligands and that its’ defucosylation altered its’ malignant phenotype.. Based on these precedents, it is reasonable to hypothesize that CD44-enriched breast cancer stem cell populations require fucose in order to exert their aggressive behavior. Assays to assess the role of fucose in these stem cells are apparent and include a battery of tests involving stem cell invasion into extracellular matrices, cell binding of antibodies or fucolectins, stem cell aggregation into spheroids, colony formation in soft agar, assessment of stem cell rolling/adhesion to endothelial cells or purified E-selectin under both static or physiological flow conditions and the ability to initiate tumors upon inoculation into animal models.

We believe that new insights into aggressive breast cancer cell behaviors can be gained through the depletion of cell surface fucose from breast cancer cells. Knowledge gained from these studies should yield new insights when using current models of human breast cancer in vitro and in vivo.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-07-04.

P2-18-06: Conventional Trastuzumab Is an Antagonist of Natural Killer Cells: Making the Case for Fucose-Depleted Trastuzumab

The discovery of the HER2 receptor and later the development of trastuzumab (an anti-HER2 antibody) were major advances leading toward the treatment of a significant proportion of human breast cancers. Trastuzumab (Herceptin®) is a humanized monoclonal IgG1 whose discrete antitumor effects are exerted through the 2 main components of the antibody. Trastuzumab's FAB portion binds to the HER2 extracellular domain, interrupting HER2 signaling. The FC portion then engages the activating receptor (FcγRIIIa) on an effector cell, usually a natural killer (NK) cell and instigates a lytic attack via antibody-dependent cellular cytotoxicity (ADCC).

The value of trastuzumab in breast cancer therapy is well established, but, there are limitations to the drug's effectiveness. These include: (1) unresponsive tumors with low or equivocal HER2 expression; (2) de novo (primary) resistance to therapy in over 50% of patients with HER2−positive tumors; (3) frequent emergence of secondary resistance often after short exposure periods; (4) competition of plasma IgG proteins with antibodies for binding to the activating FC receptors on NK cells; and (5) the high cost of trastuzumab treatment, raising concerns for the economic sustainability of this form of therapy.

Trastuzumab and other therapeutic antibodies share a structural feature that is critical to their effectiveness: a specific oligosaccharide which is covalently linked to the FC region at asparagine 297 (Asn297) in each of the 2 heavy chains. This oligosaccharide, a mannosyl-chitobiose core, is “core-fucosylated” with a single α-L-fucose (fucose) sugar attached via an α(1,6) linkage. In 2002, Shields et al. developed a novel form of trastuzumab which lacked core fucose in the Fc region [J Biol Chem 2002; 277: 26733–40]. When compared to conventional trastuzumab, the fucose-depleted trastuzumab was 43-fold more potent in provoking ADCC against HER2−expressing human breast cancer cells in vitro. Subsequent studies with several monoclonal antibodies have elucidated the role of core fucose in inhibiting ADCC, by reducing the affinity of trastuzumab's Fc portion for the activating FC receptors located on effector cells. The superior ADCC effect of fucose-depleted trastuzumab has now been demonstrated in vivo [Junttila TT et al., Cancer Res 2010; 70: 4481–4489].

We review both in vitro and in vivo evidence from multiple laboratories (working with trastuzumab, rituximab and other therapeutic antibodies) to argue that fucose-depleted trastuzumab offers several potential advantages over conventional trastuzumab. Such advantages in clinical use, we postulate, include (1) treatment of patients with trastuzumab-resistant tumors, (2) treatment of patients with equivocal or low expression of HER2, and (3) decreased cost of treatment.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-18-06.

Cell surface fucose ablation as a therapeutic strategy for malignant neoplasms

The sugar alpha-L-fucose is overexpressed in many human malignancies, especially on specific glycoproteins, glycolipids, certain mucins, and putative cell adhesion ligands found on cancer cell surfaces. Many of these molecules are known or suspected mediators of cell-cell adhesion, cell signaling, motility, or invasion. As knowledge of fucose metabolism evolves and specific mechanisms of its distribution and incorporation are more exactly documented, modulation of fucose expression in cancer is becoming increasingly more feasible. The authors propose that cancer cell surface alpha-L-fucose is a logical target for selective therapeutic ablation. Reduction of fucose content on the surfaces of malignant cells should effectively cripple the cells' physiologic functions by altering or dysregulating cell-cell or cell-matrix interactions, critical for maintaining the malignant phenotype. Significant therapeutic benefits might include modulation of adhesion abnormalities in the cancer cells, reduction of cancer cell motility or invasiveness, reexposure to immune surveillance, or a combination of these events.

MALT lymphoma presenting as a cystic salivary gland mass

BACKGROUND

Mucosa associated lymphoid tissue (MALT) lymphoma has been noted to involve the salivary glands in chronic inflammatory conditions such as Sjogren's syndrome and in HIV infection.

METHODS AND RESULTS

The authors encountered a patient with bilateral cystic changes in the parotid glands which proved to be due to MALT lymphoma. The clinical course, histopathology, and treatment options of MALT lymphoma in the salivary gland are discussed in detail.

CONCLUSION

This malignant entity should be considered in the differential diagnosis of refractory cystic lesions of the salivary glands.

A prospective trial of telepathology for intraoperative consultation (frozen sections)

Telepathology is a maturing technology that, for a variety of reasons, has not been widely deployed. In addition, clinical validation is relatively modest compared with accepted telemedicine applications such as teleradiology. A prototype telepathology system (Tele-Path(sm)) featuring high-resolution images selected from a remote microscope site has been developed at the University of Alabama at Birmingham (UAB). To validate the diagnostic efficacy of the system, a prospective study was undertaken of parallel diagnoses by conventional microscopy and telepathology with a remotely operated microscope. Slides from 99 intraoperative consultations from 29 tissue/ organ sites in the University of Alabama Hospitals by 9 academic pathologists were used in the study. Each microscopic and telepathology diagnosis was compared with the final diagnosis rendered by a referee pathologist. Diagnoses were classified as correct, false positive, or false negative or classification error. Of the 99 frozen sections evaluated, 3 cases were deferred. Of the remaining 96 cases, 2 received incorrect diagnoses in both the microscopic and telepathology arms of the study. Three errors occurred only in the telepathology arm. There was 1 false-positive diagnosis, 1 false-negative diagnosis, and 1 classification error. Statistical analysis indicated no significant difference between telepathology and conventional microscopy. Qualitative data indicated that the pathologists were generally satisfied with the performance of the system. Telepathology using this system paradigm is sufficiently accurate for real time utilization in a complex surgical environment. Telepathology therefore may be an effective model to support the surgical services of hospitals lacking full-time pathology coverage, resulting in full-time access to anatomic pathology services.

Hodgkin's and non-Hodgkin's lymphoma: spectrum of morphologic and immunophenotypic overlap

Immunoperoxidase markers are useful and often essential in distinguishing among lymphocyte-predominant Hodgkin's lymphoma, T-cell-rich B-cell lymphoma, and lymphocyte-rich classic Hodgkin's lymphoma. However, it is becoming increasingly clear that these "entities" are closely related clonal B-lineage neoplasms that may intertransform and/or coexist. We hypothesized that, just as there are cases with morphologic overlap, there would also be immunophenotypic overlap that would be found when a series of such cases is studied in detail. Eight cases of lymphocyte predominant Hodgkin's lymphoma, eight cases of lymphocyte-rich classic Hodgkin's lymphoma, seven cases of T-cell-rich B-cell lymphoma, and four cases of large B-cell lymphoma with focal features of T-cell-rich B-cell lymphoma were examined by the immunoperoxidase technique for expression of CD3, CD15, CD30, CD20, CD57, epithelial membrane antigen, and Epstein-Barr virus latent membrane protein (EBV LMP). All eight of the lymphocyte-predominant Hodgkin's lymphoma cases had CD20+ lymphocytic and histiocytic cells and CD57+ rosettes; however, in two cases, occasional lymphocytic and histiocytic cells were also weakly positive for CD15, CD30, and EBV LMP. Among the eight lymphocyte-rich classic Hodgkin's lymphoma cases, CD15+ Reed-Sternberg (R-S) cells were found in seven; however, in three of these cases rare rosettes of CD57+ cells surrounded the R-S or lacunar cells. In one case of large B-cell lymphoma the malignant cells resembled R-S cells and were CD20+, EBV LMP+, CD30+, CD15-, and surrounded by rosettes of CD57+ T cells. The majority of the cases exhibited the "expected" immunophenotypic patterns; however, the exceptional cases that were found serve to confirm the interrelationship among these clonal B-lineage neoplasms.

Composite B-cell and T-cell lymphoma arising 24 years after nodular lymphocyte predominant Hodgkin's disease

Twenty-four years after apparently successful treatment for nodular lymphocyte predominant Hodgkin's disease (nLPHD), a 41-year old male developed "B" symptoms and extensive adenopathy. A right axillary lymph node biopsy showed two distinct regions including (1) histiocyte-rich B-cell lymphoma and (2) diffuse small T-cell lymphoma. A clonal rearrangement of the gene for the T-cell receptor beta chain confirmed the presence of a T-cell neoplasm, and this was further confirmed by selective polymerase chain reaction (PCR) on this morphologic zone. PCR on the morphologic B-cell lymphoma confirmed the presence of an immunoglobulin gene rearrangement. These two regions were separated by a less-defined zone containing a mixture of small CD57 positive T lymphocytes, small B lymphocytes, and rare lymphocytic and histiocytic (L&H) cells, highly suggestive of recurrent LPHD. The development of composite B-cell and T-cell lymphoma in this patient raises the speculation that nLPHD may be a neoplasm of lymphoid cells, which can differentiate in both B- and T-cell directions, with the "L&H" cells constituting their B-cell progeny.

Alpha-L-fucose: a potentially critical molecule in pathologic processes including neoplasia

Alpha-L-fucose is a 6-carbon deoxyhexose that is commonly incorporated into human glycoproteins and glycolipids. It is found at the terminal or preterminal positions of many cell-surface oligosaccharide ligands that mediate cell-recognition and adhesion-signaling pathways. These include such normal events as early embryologic development and blood group recognition and pathologic processes including inflammation, infectious disease recognition, and neoplastic progression. Fucosylated oligosaccharide ligands mediate cell-cell adhesion through binding to cell-surface selectins (calcium-dependent binding proteins) and calcium-dependent interactions with other cell-surface carbohydrate counterligands. A number of fucose-containing "natural ligands" are common to inflammatory and malignant cell processes. We review evidence that alpha-L-fucose is critically important for cell-cell and cell-matrix adhesion in a variety of normal and pathologic processes, particularly neoplasia. Current results suggest that alpha-L-fucose provides the essential structure that enables carbohydrate ligands to bind to selectins and to carbohydrate counterligands and thereby alter cellular homeostasis.

An initial trial of a prototype telepathology system featuring static imaging with discrete control of the remote microscope

Routine diagnosis of pathology images transmitted over telecommunications lines remains an elusive goal. Part of the resistance stems from the difficulty of enabling image selection by the remote pathologist. To address this problem, a telepathology microscope system (TelePath, TeleMedicine Solutions, Birmingham, Ala) that has features associated with static and dynamic imaging systems was constructed. Features of the system include near real time image transmission, provision of a tiled overview image, free choice of any fields at any desired optical magnification, and automated tracking of the pathologist's image selection. All commands and images are discrete, avoiding many inherent problems of full motion video and continuous remote control. A set of 64 slides was reviewed by 3 pathologists in a simulated frozen section environment. Each pathologist provided diagnoses for all 64 slides, as well as qualitative information about the system. Thirty-one of 192 diagnoses disagreed with the reference diagnosis that had been reached before the trial began. Qf the 31, 13 were deferrals and 12 were diagnoses of cases that had a deferral as the reference diagnosis. In 6 cases, the diagnosis disagreed with the reference diagnosis yielding an overall accuracy of 96.9%. Confidence levels in the diagnoses were high. This trial suggests that this system provides high-quality anatomic pathology services, including intraoperative diagnoses, over telecommunications lines.

Solitary breast metastasis to the ampulla and distal common bile duct

The indications for pancreaticoduodenectomy have continued to expand over the past 10 to 15 years. This is in large part due to improved diagnostic studies, endoscopic retrograde cholangiopancreaticogram and computed tomography, and decreases in hospital perioperative morbidity and mortality. One third of breast cancer patients will develop metastatic disease usually to the liver, lung, or bone (World J Surg 1994;18:98-111). However, the presentation of painless jaundice due to a single metastatic lesion to the distal common bile duct from ductal adenocarcinoma of the breast is extremely rare. In this case report and review of the literature, we discuss the indications and emerging evidence that pancreaticoduodenectomies can now be performed for localized metastatic disease.

Trilineage extramedullary myeloid cell tumor in myelodysplastic syndrome

A patient with a 17-month history of myelodysplastic syndrome (refractory anemia with excess blasts that evolved into chronic myelomonocytic leukemia), which was treated with transfusions and erythropoietin, developed abdominal and inguinal lymphadenopathy. Biopsies of the abdominal nodes revealed virtual obliteration of the architecture by myeloid blasts admixed with maturing granulocytic, erythroid, and megakaryocytic precursors. The lymph node findings appeared to represent extramedullary dyshematopoiesis undergoing a tissue phase blast transformation. Four months later, the patient developed rising peripheral blast counts consistent with acute leukemia. Although the development of granulocytic sarcoma (also called extramedullary myeloid cell tumor) is well known to occur in patients with myelodysplastic syndromes, to our knowledge this is the first description of an extramedullary myeloid cell tumor associated with trilineage differentiation.

Ultrastructural and immunocytochemical features of a case of neuroendocrine carcinoma developing in a prior ileostomy site

A patient who developed a mixed neuroendocrine carcinoma and adenocarcinoma at the site of a previous long-standing ileostomy is reported. The neuroendocrine features are documented by both ultrastructural and immunocytochemical findings. Carcinoma arising in an ileostomy site is rare but has been recorded in patients with long-standing ileostomies after colectomy for chronic inflammatory bowel disease, as in this patient. Neuroendocrine carcinoma developing in this setting apparently has not been described before, however.

CT manifestation of non-Hodgkin's lymphoma as a solitary pulmonary nodule in a patient with acquired immunodeficiency syndrome

We present a case of acquired immunodeficiency syndrome with primary pulmonary non-Hodgkin's lymphoma that manifested as a solitary pleura-based mass lesion. Its differentiation from an infectious process imposed a diagnostic dilemma. The importance of awareness of such an entity for earlier diagnosis is stressed.

Serum response heterogeneity among nonsmall cell lung cancer cell lines

This study examined the morphology, in vitro growth, and two genetic responses to serum stimulation in the nonsmall cell lung cancer (NSCLC) cell lines SK-Lu-1, SK-MES-1, A427, and A549. Morphologically, all four were NSCLC: SK-Lu-1 was undifferentiated, the remainder were adenocarcinoma variants. SK-Lu-1 and SK-MES-1 were slow growing with low-anchorage independent growth capacity; the A427 and A549 lines were fast growing with high-anchorage independent growth capacity. All of the lines expressed basic fibroblast growth factor (bFGF) as a dominant 7.1 kb transcript at amounts significantly lower than in control human lung fibroblasts. bFGF expression could be upregulated by serum exposure in several nontransformed human cell lines, but only the SK-Lu-1 NSCLC cells increased bFGF after serum exposure (482%) compared with a peak increase of 1222% in the fibroblast controls. All of the NSCLC cell lines increased c-fos in response to the same serum stimulations. These results show that growth-factor gene expression can be modulated in NSCLC, and that significant differences exist among NSCLC cell lines commonly used as laboratory correlates of human disease.

Acute congestive heart failure in a 55-year-old man. Rheumatic carditis diagnosed by endomyocardial biopsy

We describe a 55-year-old man who presented with acute left ventricular dysfunction and congestive heart failure caused by rheumatic carditis. The diagnosis of rheumatic carditis was established by percutaneous endomyocardial biopsy. Since many physicians may not be familiar with some of the clinical and histopathologic features of rheumatic carditis, we submit this report as a reminder that the disease has not disappeared, should be considered in the differential diagnosis of acute heart failure, and can be diagnosed by endomyocardial biopsy.

Common reactive erythrophagocytosis in axillary lymph nodes

Erythrophagocytosis by histiocytes in the sinuses of axillary lymph nodes is a common yet little-known phenomenon. The axillary lymph node dissections of 23 patients were studied by light microscopy and graded for the amount of erythrophagocytosis. None of the patients had evidence of a systemic hemolytic process. Nineteen of them exhibited some degree of erythrophagocytosis, and this was present even in four of the six patients who never had a prior breast biopsy. Breast biopsy was associated with massive degrees of erythrophagocytosis in 8 of 17 patients, and after a postbiopsy interval of two weeks 11 of 13 patients had hemosiderin deposition in the lymph nodes, evidence of red blood cell breakdown. This study serves to substantiate statements, made by others without confirmatory data, that large degrees of erythrophagocytosis may be seen in axillary lymph nodes after breast biopsies and that small amounts of erythrophagocytosis may be identified in lymph nodes of patients with no prior trauma history.

Variable ploidy of ovarian clear cell carcinomas. Implications for adequacy of tissue sampling

Ten cases of clear cell (mesonephroid) adenocarcinoma of the ovary were examined for (1) variations of morphology within each tumor and its metastases, (2) ploidy of each morphologic region and (3) clinical behavior. Correlations were sought among these factors. Analysis of the ploidy in up to six morphologic regions per tumor showed variations in the ploidy in seven of the ten cases, with all seven having both diploid and nondiploid regions. The presence or absence of abnormal ploidy was not predictable based on the histomorphologic appearance of a given section. These results suggest that (1) the evaluation of a single random tissue sample may not discover aneuploidy that is present and (2) future ploidy studies on malignant tumors may require extensive tumor sampling in order to definitively exclude the presence of aneuploid populations.

Patterns of mucin secretion in neoplastic and non-neoplastic diseases of the colon

Changes in the pattern of sulfomucin and sialomucin secretion and height of large bowel mucosa have been described adjacent to primary colonic adenocarcinomas and adenomas, and called "transitional" mucosa. These changes were initially thought to be specific preneoplastic changes. In this study "transitional" changes in colonic and rectal mucosa were found in some cases overlying benign mesenchymal tumors, metastatic tumors from noncolonic sites, and sites of endometriosis, as well as adjacent to primary colonic and rectal neoplasms. These findings suggest that although these changes may be found adjacent to primary large bowel neoplasms, they are frequently secondary reactive rather than primary preneoplastic phenomena. In addition, the thickness of the mucosa and the accompanying pattern of mucin secretion usually seen in transitional mucosa may be dissociated.