Biomimetic biodegradable artificial antigen presenting cells synergize with PD-1 blockade to treat melanoma.

Biomimetic materials that target the immune system and generate an anti-tumor responses hold promise in augmenting cancer immunotherapy. These synthetic materials can be engineered and optimized for their biodegradability, physical parameters such as shape and size, and controlled release of immune-modulators. As these new platforms enter the playing field, it is imperative to understand their interaction with existing immunotherapies since single-targeted approaches have limited efficacy. Here, we investigate the synergy between a PLGA-based artificial antigen presenting cell (aAPC) and a checkpoint blockade molecule, anti-PD1 monoclonal antibody (mAb). The combination of antigen-specific aAPC-based activation and anti-PD-1 mAb checkpoint blockade induced the greatest IFN-γ secretion by CD8+ T cells in vitro. Combination treatment also acted synergistically in an in vivo murine melanoma model to result in delayed tumor growth and extended survival, while either treatment alone had no effect. This was shown mechanistically to be due to decreased PD-1 expression and increased antigen-specific proliferation of CD8+ T cells within the tumor microenvironment and spleen. Thus, biomaterial-based therapy can synergize with other immunotherapies and motivates the translation of biomimetic combinatorial treatments.

Nasopharyngeal carcinoma in situ: two cases of an emerging diagnostic entity.

BACKGROUND: The association of Epstein-Barr virus (EBV) with the oncogenesis of nasopharyngeal carcinoma (NPC) is well established. Latent infection by EBV with clonal proliferation has also been demonstrated in preinvasive lesions of NPC. In situ hybridization for EBV-encoded RNA (ISH EBER) now serves as an ancillary test in the definitive diagnosis of these lesions. METHODS: Two cases of nasopharyngeal carcinoma in situ (NPCIS) are presented in this study. Their biopsies were studied by ordinary light microscopy, the ISH EBER technique, and immunostaining for bcl-2. Tissue samples from 100 high risk subjects negative for NPC and NPCIS, who served as controls, were also studied using the ISH EBER technique. RESULTS: NPCIS was characterized by abnormal light microscopic appearance as well as positive staining by the ISH EBER technique; these features were not observed in samples from the 100 high risk subjects. Immunostaining for bcl-2 protein was positive but less specific. Postradiotherapy biopsies of the two patients were negative for NPCIS. CONCLUSIONS: With the help of the ISH EBER technique, the diagnosis of NPCIS is now possible in routine surgical pathology. As this entity is rare, it is necessary to have a high degree of suspicion when evaluating biopsies from high risk individuals. Radiotherapy for patients with NPCIS is justified in view of the risk of cancer progression and the possibility of a coexisting invasive carcinoma.

Monocyte chemoattractant protein-1 (MCP-1) expression in primary lymphoepithelioma-like carcinomas (LELCs) of the lung.

Lymphoepithelioma-like carcinoma (LELC) of the lung is a recently recognized primary non-small cell lung carcinoma with distinct clinicopathological features and an aetiological association with Epstein-Barr virus (EBV) infection. The tumour consists of clusters and sheets of poorly or undifferentiated tumour cells in close association with numerous mononuclear inflammatory cells, including a rich component of tumour-associated macrophages (TAMs). To investigate the molecular mechanism leading to the TAM-rich stroma, the expression of a monocyte-specific chemotactic and activating factor, monocyte chemoattractant protein-1 (MCP-1), was studied by reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH), and the presence of TAMs was demonstrated by immunohistochemistry in nine LELCs. The results were compared with those found in 17 conventional non-small cell lung carcinomas. RT-PCR showed specific MCP-1 amplification in both LELCs and non-LELCs, but ISH demonstrated a unique and extensive expression of MCP-1 transcripts by the tumour cells of LELCs only, while TAMs, stromal fibroblasts, and endothelial cells formed the major source of MCP-1 in non-LELCs. TAMs in LELCs were more abundant and showed a close topographical relationship with the MCP-1-expressing tumour cells. The results indicate that tumour cell expression of MCP-1 in LELCs is an important mechanism contributing to their distinctive morphological features. This is the first study that demonstrates the in vivo upregulation of a monocyte-specific chemokine by EBV-related carcinomas, illustrating an interesting aspect of tumour biology in EBV-related neoplasms.

Expression of p53 in oesophageal squamous cell carcinoma in Hong Kong Chinese.

We studied p53 overexpression in a series of 99 primary oesophageal squamous cell carcinomas (28 well-differentiated, 42 moderately-differentiated and 29 poorly-differentiated squamous cell carcinomas) from Chinese patients using the p53 protein specific mouse monoclonal antibody DO-7 on paraffin sections. The p53 protein was detected in 30% (30 cases) of the tumours. A significantly higher positive rate was noted in the poorly-differentiated tumours (11% for the well-differentiated, 31% for the moderately-differentiated and 48% for the poorly-differentiated tumours). In addition, strong positive p53 staining was identified only in the less differentiated tumour cells in the periphery of the tumour cell nests in all the cases and the expression was weaker in the better differentiated foci. The central keratinizing areas and the immediately adjacent tumour cells were always negative for p53. The adjacent normal oesophageal mucosa was all negative for p53 protein but the non-invasive dysplastic epithelium next to the tumours could also be strongly positive for p53 protein (four out of 14 cases in which the dysplastic epithelium adjacent to the tumour was adequately sampled). In two out of these four cases, the dysplastic epithelium showed staining for p53; even the adjacent invasive tumour was negative for p53. It is concluded that there is a strong relationship between p53 overexpression and tumour cell differentiation in oesophageal squamous carcinoma and overexpression of p53 can occur in non-invasive tumour cells.

Clonal Epstein-Barr virus in lymphoepithelioma-like carcinoma of the stomach: demonstration of viral genome by in situ hybridization and Southern blot analysis.

Lymphoepithelioma (LE), originally described in the nasopharynx, is an undifferentiated carcinoma with heavy lymphocytic infiltrate. The tumor is common in Southeast Asia, particularly in southern China, where the Epstein-Barr virus (EBV) association has been documented more consistently than in Western countries. Tumors histologically similar to LE have been described also in other anatomical sites, mostly of fore-gut origin, such as salivary gland, tonsil, lung, thymus, and more recently stomach. We are reporting a case of poorly differentiated gastric adenocarcinoma with marked lymphocytic infiltrate resembling LE (LE-like carcinoma) in a Chinese without evidence of nasopharyngeal carcinoma. In situ hybridization for EBV revealed that the tumor cells but not the lymphoid cells harbored the virus. Tumor cells both in syncytial and glandular areas were positive for EBV. By Southern blot analysis EBV was demonstrated in the DNA extracted from the tumor, while the adjacent normal gastric tissue was negative. Moreover, analysis of the EBV termini revealed a clonal episomal form of the virus. Our case further supports the hypothesis that EBV is associated with LE-like gastric carcinoma. It also strongly suggests that EBV infection has preceded, and thus most likely contributed to, the clonal expansion in this tumor.

Localisation of CD10 to biliary canaliculi by immunoelectron microscopical examination.

Common acute lymphoblastic leukaemia antigen (CALLA) was first characterised in lymphoid leukaemic cells. The antigen is present in different stages of lymphoid cell differentiation as well as in subsets of myeloid cells, and further studies have also shown its presence in non-lymphoid tissues. The recent cloning and sequencing of the gene permitted deduction of its amino acid sequence which is identical with the human membrane-associated enzyme, neutral endopeptidase. Strong immunostaining for CALLA was detected in the human liver with a canalicular pattern. Immunoelectron microscopy also confirmed that the antigen was localised only in the area of the bile canaliculi. Although the function of neutral endopeptidase in the canaliculi is unknown, this antigen may prove useful in the study of biliary function and diseases.

Rapid demonstration of Campylobacter in gastric biopsies using microwave irradiation.

With the aid of microwave irradiation, a modified method for rapid detection of Campylobacter has been devised. Compared with the conventional Warthin-Starry method, both staining period and concentration of the silver solution are considerably reduced but there is excellent staining and good tissue morphology.