Bovine Meat and Milk Factor-like Sequences Are Frequently Detected in Renal Cell Carcinoma Tissues

Previous studies have indicated a potential role of diet in the pathogenesis of renal cell carcinoma (RCC). Recently, circular bovine meat and milk factor (BMMF) DNAs have been identified in peritumoral tissues of human colon and breast cancers. Here, we investigated the prevalence of the DNA of these novel human pathogenic infectious agents in RCC and adjacent peritumoral renal tissues. DNA was extracted from formalin-fixed and paraffin-embedded (FFPE) RCC and peritumoral kidney tissues, including a test (n = 11) and a validation (n = 152) collection. BMMF1 and BMMF2 consensus primers were designed to screen for the presence of BMMF1- and BMMF2-like DNA. In addition, BMMF-specific PCR was performed on selected cases to test for the presence of additional regions of BMMF1 and BMMF2 genomes. A reference collection of hepatocellular carcinomas (HCCs; n = 60) and adjacent peritumoral liver tissues (n = 50) was also included. Our results demonstrated that BMMF1 and BMMF2 DNAs are frequently found in human RCC tissues and are particularly more prevalent in peritumoral kidney tissues. Of note, BMMF1 and BMMF2 genotype heterogeneity was higher in peritumoral kidney tissues compared to RCC tissues. This is the first study to directly test human FFPE tissues for BMMF1- and BMMF2-like DNA using consensus PCR and demonstrate BMMF DNA in neoplastic and peritumoral kidney tissues. The findings are in line with the recently proposed indirect etiopathogenetic role of BMMFs in, e.g., colorectal carcinogenesis. Follow-up studies are needed to explore the potential role of BMMFs in the etiopathogenesis of RCC.

Rethinking the biology of metastatic melanoma: a holistic approach

Over the past decades, melanoma-related mortality has remained nearly stable. The main reason is treatment failure of metastatic disease and the inherently linked knowledge gap regarding metastasis formation. In order to elicit invasion, melanoma cells manipulate the tumor microenvironment, gain motility, and adhere to the extracellular matrix and cancer-associated fibroblasts. Melanoma cells thereby express different cell adhesion molecules like laminins, integrins, N-cadherin, and others. Epithelial-mesenchymal transition (EMT) is physiological during embryologic development, but reactivated during malignancy. Despite not being truly epithelial, neural crest-derived malignancies like melanoma share similar biological programs that enable tumorigenesis, invasion, and metastasis. This complex phenomenon is termed phenotype switching and is intertwined with oncometabolism as well as dormancy escape. Additionally, it has been shown that primary melanoma shed exosomes that create a favorable premetastatic niche in the microenvironment of secondary organs and lymph nodes. Although the growing body of literature describes the aforementioned concepts separately, an integrative holistic approach is missing. Using melanoma as a tumor model, this review will shed light on these complex biological principles in an attempt to clarify the mechanistic metastatic pathways that dictate tumor and patient fate.

Emerging role of human polyomaviruses 6 and 7 in human cancers

BACKGROUND

Currently 12 human polyomaviruses (HPyVs) have been identified, 6 of which have been associated with human diseases, including cancer. The discovery of the Merkel cell polyomavirus and its role in the etiopathogenesis in the majority of Merkel cell carcinomas has drawn significant attention, also to other novel HPyVs. In 2010, HPyV6 and HPyV7 were identified in healthy skin swabs. Ever since it has been speculated that they might contribute to the etiopathogenesis of skin and non-cutaneous human cancers.

MAIN BODY

Here we comprehensively reviewed and summarized the current evidence potentially indicating an involvement of HPyV6 and HPyV7 in the etiopathogenesis of neoplastic human diseases. The seroprevalence of both HPyV6 and 7 is high in a normal population and increases with age. In skin cancer tissues, HPyV6- DNA was far more often prevalent than HPyV7 in contrast to cancers of other anatomic sites, in which HPyV7 DNA was more frequently detected.

CONCLUSION

It is remarkable to find that the detection rate of HPyV6-DNA in tissues of skin malignancies is higher than HPyV7-DNA and may indicate a role of HPyV6 in the etiopathogenesis of the respected skin cancers. However, the sheer presence of viral DNA is not enough to prove a role in the etiopathogenesis of these cancers.

Integrative histopathological and immunophenotypical characterisation of the inflammatory microenvironment in spitzoid melanocytic neoplasms

AIMS

The role of inflammation in conventional cutaneous melanoma has been extensively studied, whereas only little is known about the inflammatory microenvironment and immunogenic properties of spitzoid melanocytic neoplasms. The composition of infiltrating immune cells and the architectural distribution of the inflammation, in particular, are still obscure. This is the first study, to our knowledge, to systematically characterise the inflammatory patterns and the leucocyte subsets in spitzoid melanocytic lesions.

METHODS AND RESULTS

We examined 79 spitzoid neoplasms including banal Spitz naevi (SN, n = 50), atypical Spitz tumours (AST, n = 17) and malignant Spitz tumours (MST, n = 12) using histopathological analysis and immunohistochemistry. Spitzoid melanocytic lesions showed a high frequency (67.1%, n = 53 of 79) of inflammation. Four inflammatory patterns were identified according to architectural composition, distribution and intensity of inflammation. The majority of the inflammatory infiltrate corresponded to CD3+ /CD8+ T lymphocytes (56.1%), followed by CD3+ /CD4+ T cells (35.7%) and CD68+ histiocytes (20.3%). CD3+ /TIA-1+ cytotoxic T lymphocytes constituted 3.7% of inflammatory cells. Rarely, CD3+ / granzyme B+ cytotoxic T lymphocytes (2.7%) and CD138+ plasma cells (0.5%) were detected in the infiltrating immune cells. There was no significant difference in the inflammatory cellular composition among the spitzoid melanocytic subgroups (SN versus AST versus MST).

CONCLUSION

Our findings demonstrate that Spitz tumours are highly immunogenic lesions. Inflammation with the presence of lymphocytic aggregates predominated in SN, but was not distinctive for this melanocytic category. A strong and intense inflammation was suggestive of an underlying malignancy. The infiltrating cytotoxic T lymphocyte subsets in Spitz tumours deserve further investigation in larger study cohorts to elucidate prognostic and immuno-oncological therapeutic relevance.

Navitoclax combined with Alpelisib effectively inhibits Merkel cell carcinoma cell growth in vitro

Background:

Merkel cell carcinoma (MCC) is a highly malignant skin cancer. Despite major treatment improvements during the last decade, up to 50% of patients do not respond to therapy or develop recurrent disease. For these patients, alternative treatment options are urgently needed. Here, we assessed the efficacy of the combination of the BCL-2 inhibitor Navitoclax and the PI3K p110α inhibitor Alpelisib in MCC cell lines.

Methods:

The expression of BCL-2 was assessed by immunohistochemistry in MCC and MCC cell lines. Treatment with Navitoclax and Alpelisib alone and in combination was performed on four MCC cell lines. The decrease of cell viability during treatment was assessed by XTT assay and visualized for the combinations by 3D combinatorial index plotting. The increase of apoptotic cells was determined by cleaved PARP Western blotting and Annexin V staining.

Results:

Some 94% of MCCs and all three MCPyV-positive cell lines showed BCL-2 expression. Navitoclax monotreatment was shown to be highly effective when treating BCL-2-positive cell lines (IC₅₀-values ranging from 96.0 to 323.0 nM). The combination of Alpelisib and Navitoclax resulted in even stronger synergistic and prolonged inhibitions of MCC cell viability through apoptosis up to 4 days.

Discussion:

Our results show that the anti-apoptotic BCL-2 is frequently expressed in MCC and MCC cell lines. Inhibition of BCL-2 by Navitoclax in combination with Alpelisib revealed a strong synergy and prolonged inhibition of MCC cell viability and induction of apoptosis. The combination of Navitoclax and Alpelisib is a novel potential treatment option for MCC patients.

High Prevalence of Human Polyomavirus 7 in Cholangiocarcinomas and Adjacent Peritumoral Hepatocytes: Preliminary Findings

Cholangiocarcinoma (CCA) is a rare biliary-duct malignancy with poor prognosis. Recently, the presence of the human polyomavirus 6 (HPyV6) has been reported in the bile of diverse hepatobiliary diseases, particularly in the bile of CCA patients. Here, we investigated the presence of novel HPyVs in CCA tissues using diverse molecular techniques to assess a possible role of HPyVs in CCA. Formalin-Fixed Paraffin-Embedded (FFPE) tissues of 42 CCA patients were included in this study. PCR-based screening for HPyVs was conducted using degenerated and HPyV-specific primers. Following that, we performed FISH, RNA in situ hybridization (RNA-ISH), and immunohistochemistry (IHC) to assess the presence of HPyVs in selected tissues. Of all 42 CCAs, 25 (59%) were positive for one HPyV, while 10 (24%) CCAs were positive for 2 HPyVs simultaneously, and 7 (17%) were negative for HPyVs. Of the total 35 positive CCAs, 19 (45%) were positive for HPyV7, 4 (9%) for HPyV6, 2 (5%) for Merkel cell polyomavirus (MCPyV), 8 (19%) for both HPyV7/MCPyV, and 2 (5%) for both HPyV6/HPyV7 as confirmed by sequencing. The presence of viral nucleic acids was confirmed by specific FISH, while the RNA-ISH confirmed the presence of HPyV6 on the single-cell level. In addition, expression of HPyV7, HPyV6, and MCPyV proteins were confirmed by IHC. Our results strongly indicate that HPyV7, HPyV6, and MCPyV infect bile duct epithelium, hepatocytes, and CCA cells, which possibly suggest an indirect role of these viruses in the etiopathogenesis of CCA. Furthermore, the observed hepatotropism of these novel HPyV, in particular HPyV7, might implicate a role of these viruses in other hepatobiliary diseases.

A digital mRNA expression signature to classify challenging Spitzoid melanocytic neoplasms

Spitzoid neoplasms are a challenging group of cutaneous melanocytic proliferations. They are characterized by epithelioid and/or spindle-shaped melanocytes and classified as benign Spitz nevi (SN), atypical Spitz tumors (AST), or malignant Spitz tumors (MST). The intermediate AST category represents a diagnostically challenging group since on purely histopathological grounds, their benign or malignant character remains unpredictable. This results in uncertainties in patient treatment and prognosis. The molecular properties of Spitzoid lesions, especially their transcriptomic landscape, remain poorly understood, and genomic alterations in melanoma-associated oncogenes are typically absent. The aim of this study was to characterize their transcriptome with digital mRNA expression profiling. Formalin-fixed paraffin-embedded samples (including 27 SN, 10 AST, and 14 MST) were analyzed using the NanoString nCounter PanCancer Pathways Panel. The number of significantly differentially expressed genes in SN vs. MST, SN vs. AST, and AST vs. MST was 68, 167, and 18, respectively. Gene set enrichment analysis revealed upregulation of pathways related to epithelial-mesenchymal transition and immunomodulatory-, angiogenesis-, hormonal-, and myogenesis-associated processes in AST and MST. A molecular signature of SN vs. MST was discovered based on the top-ranked most informative genes: NRAS, NF1, BMP2, EIF2B4, IFNA17, and FZD9. The AST samples showed intermediate levels of the identified signature. This implies that the gene signature can potentially be used to distinguish high-grade from low-grade AST with a larger study cohort in the future. This combined histopathological and transcriptomic methodology is promising for prospective diagnostics of Spitzoid neoplasms and patient management in dermatological oncology.

The curious case of Merkel cell carcinoma: epigenetic youth and lack of pluripotency

Merkel cell carcinoma (MCC) is a very rare, but highly aggressive skin cancer which occurs mainly in elderly patients. MCC cells show an expression pattern of three cell lineages: epithelial, neuroendocrine, and B-cell progenitor. This trilinear expression pattern suggests stemness activity in MCC. The etiopathogenesis of MCC is either linked to the Merkel cell polyomavirus (MCPyV) or in a smaller proportion (20%) to high levels of UV-induced somatic mutations. Both viral presence and accumulation of mutations have been shown to be associated with accelerated DNA methylation Age (DNAmAge) compared to chronological age. The MCC DNAmAge was significantly lower compared to the chronological age, which was irrespective of the viral presence or mutational burden. Although these features indicate some aspects of stemness in MCC cells, gene-expression-based pluripotency testing did not provide evidence for pluripotency of MCC cells.

Genomic Landscape of Spitzoid Neoplasms Impacting Patient Management

Spitzoid neoplasms are a distinct group of melanocytic proliferations characterized by epithelioid and/ or spindle shaped melanocytes. Intermediate forms that share features of both benign Spitz nevi (SN) and Spitz melanoma, i.e., malignant Spitz tumor (MST) represent a diagnostically and clinically challenging group of melanocytic lesions. A multitude of descriptive diagnostic terms exist for these ambiguous lesions with atypical Spitz tumor (AST) or Spitz tumor of uncertain malignant potential (STUMP) just naming two of them. This diagnostic gray zone creates confusion and high insecurity in clinicians and in patients. Biological behavior and clinical course of this intermediate group still remains largely unknown, often leading to difficulties with uncertainties in clinical management and prognosis. Consequently, a better stratification of Spitzoid neoplasms in benign and malignant forms is required thereby keeping the diagnostic group of AST/STUMP as small as possible. Ancillary diagnostic techniques such as immunohistochemistry, comparative genomic hybridization, fluorescence in situ hybridization, next generation sequencing, micro RNA and mRNA analysis as well as mass spectrometry imaging offer new opportunities for the distinct diagnosis, thereby allowing the best clinical management of Spitzoid neoplasms. This review gives an overview on these additional diagnostic techniques and the recent developments in the field of molecular genetic alterations in Spitzoid neoplasms. We also discuss how the recent findings might facilitate the diagnosis and stratification of atypical Spitzoid neoplasms and how these findings will impact the diagnostic work up as well as patient management. We suggest a stepwise implementation of ancillary diagnostic techniques thereby integrating immunohistochemistry and molecular pathology findings in the diagnosis of challenging ambiguous Spitzoid neoplasms. Finally, we will give an outlook on pending future research objectives in the field of Spitzoid melanocytic lesions.

Phosphatidylinositol 3-kinase p110δ expression in Merkel cell carcinoma

The prognosis of stage III/IV Merkel cell carcinoma (MCC) is very poor. The Phosphatidylinositol 3-kinase p110δ specific inhibitor idelalisib has recently been reported to induce complete clinical remission in a stage IV MCC patient. Here we assessed the expression of p110δ in primary MCC and MCC cell lines including its functionality. Immunofluorescence microscopy revealed a specific cytoplasmic p110δ expression in 71.4% of the tested MCCs and in all tested MCC cell lines. Compared to the B cell leukemia cell line REH all MCC cell lines, except MKL-1, revealed a lower response towards the treatment with idelalisib. MKL-1 showed a 10-fold higher IC₅₀ compared to REH which was accompanied by a significant decrease of Akt phosphorylation. However, treating the MCC cells with the specific PI3K p110α subunit inhibitor BYL719 led to a more effective decrease of the cell viability compared to idelalisib: WaGa cells 30-fold, PeTa cells 15-fold and all other MCC cell lines 3-fold. Although PI3K p110δ is expressed in the majority of MCCs and cell lines its inhibition by idelalisib alone does not suffice to effectively affect MCC cells viability.

Detection of Merkel Cell Polyomavirus in Seborrheic Keratosis

Seborrheic keratosis (SK) is the most common benign cutaneous neoplasm. A subset shows increased p16 expression. Since SK shares several features with verruca vulgaris, e.g., increased p16 expression, human papillomaviruses (HPV) have been suggested as possible causal agents. However, a relevant association could not be established between HPV and SK. In the present study we aimed to investigate the presence of Merkel cell polyomavirus (MCPyV) in relation to p16 expression in SK. P16 expression was investigated using immunohistochemistry (IHC). Presence of MCPyV was assessed in 23 formalin-fixed paraffin-embedded tissue samples of SK by molecular techniques (i.e., PCR and FISH) and IHC. 16/23 SK showed strong to moderate p16 expression. 6/23 of SK were MCPyV positive by PCR which was confirmed by FISH. Of interest, two samples with strong FISH signals also showed MCPyV expression as tested by IHC. Samples with weaker signal intensity were negative in IHC. P16 expression was not associated with the presence of MCPyV. Concluding, the detection of MCPyV DNA by PCR and FISH in SK reflects the widespread prevalence of MCPyV in the skin. However, low detection rates exclude MCPyV as a major pathogenic factor in SK, most likely representing a coincidental infection. P16 IHC does not appear as useful adjunctive surrogate marker for the presence of MCPyV in SK.

Reviewing the current evidence supporting early B-cells as the cellular origin of Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a highly malignant skin cancer characterized by early metastases and poor survival. Although MCC is a rare malignancy, its incidence is rapidly increasing in the U.S. and Europe. The discovery of the Merkel cell polyomavirus (MCPyV) has enormously impacted our understanding of its etiopathogenesis and biology. MCCs are characterized by trilinear differentiation, comprising the expression of neuroendocrine, epithelial and B-lymphoid lineage markers. To date, it is generally accepted that the initial assumption of MCC originating from Merkel cells (MCs) is unlikely. This is owed to their post-mitotic character, absence of MCPyV in MCs and discrepant protein expression pattern in comparison to MCC. Evidence from mouse models suggests that epidermal/dermal stem cells might be of cellular origin in MCC. The recently formulated hypothesis of MCC originating from early B-cells is based on morphology, the consistent expression of early B-cell lineage markers and the finding of clonal immunoglobulin chain rearrangement in MCC cells. In this review we elaborate on the cellular ancestry of MCC, the identification of which could pave the way for novel and more effective therapeutic regimens.

PET imaging of zirconium-89 labelled cetuximab: A phase I trial in patients with head and neck and lung cancer

BACKGROUND AND PURPOSE

PET imaging of cetuximab uptake may help selecting cancer patients with the highest chance of benefit. The aim of this phase I trial was to determine the safety of the tracer ⁸⁹Zr-cetuximab and to assess tumour uptake.

METHODS

Two dose schedules were used; two consecutive doses of 60MBq ⁸⁹Zr-cetuximab or a single dose of 120MBq, both preceded by 400mg/m² of unlabelled cetuximab. Toxicity (CTCAE 3.0) was scored twice weekly. PET-CT scans were acquired on days 4, 5 and 6 (step 1) or 5, 6, 7 (step 2). Because tumour uptake could not be assessed satisfactorily, a third step was added including EGFR overexpressing tumours.

RESULTS

Nine patients were included (6 NSCLC; 3 HNC). No additional toxicity was associated with administration of ⁸⁹Zr-cetuximab compared to standard cetuximab. A tumour to blood ratio (TBR)>1 was observed in all but one patient, with a maximum of 4.56. TBR was not different between dose schedules. There was a trend for higher TBR at intervals>5days after injection.

CONCLUSIONS

Both presented ⁸⁹Zr-cetuximab administration schedules are safe. The recommended dose for future trials is 60MBq, with a minimum time interval for scanning of 6days.

Frequent detection of human polyomavirus 6 in keratoacanthomas

BACKGROUND

The recent discovery of the Merkel cell polyomavirus and its consistent association with Merkel cell carcinoma has drawn attention to the numerous recently discovered polyomaviruses and their possible involvement in the etiopathogenesis of non-melanoma skin cancer (NMSC). Data on the recently discovered human polyomavirus 6 (HPyV6) and its role in NMSC are sparse and in part controversial.

METHODS

In the present study we tested a large number (n = 299) of NMSC specimens for the presence of human polyomavirus 6 (HPyV6) by DNA PCR and HPyV6 fluorescence in situ hybridization (FISH). In detail, 59 keratoacanthomas (KA), 109 basal cell carcinomas (BCC), 86 squamous cell carcinomas (SCC) and 45 trichoblastomas (TB) were tested for the presence of HPyV6.

RESULTS

HPyV6 DNA PCR and subsequent sequence analysis revealed that 25 KAs (42.3 %), 23 BCCs (21.1 %), 8 SCCs (9.3 %) and 10 TBs (22.2 %) were HPyV6 positive. The presence of HPyV6 DNA was visualized and validated on the single cell level within the histomorphological context by HPyV6 fluorescence in situ hybridization.

CONCLUSIONS

The high frequency of HPyV6 DNA in 42.3 % of KA possibly points to a role for HPyV6 in the etiopathogenesis of KAs. Although the detection rate of HPyV6 DNA in BCCs and TBs is within the previously reported detection range in normal skin, it does not exclude a possible role for HPyV6 in the carcinogenesis in a significant subset of these skin tumors.

Id1 overexpression is independent of repression and epigenetic silencing of tumor suppressor genes in melanoma

The full molecular consequences of oncogene activation during tumorigenesis are not well understood, but several studies have recently linked oncogene activation to epigenetic silencing of specific genes 1, 2. Transcriptional repressor Id1 is overexpressed in many malignancies including melanoma, and Id1 targets include tumor suppressor genes TSP1, CDKN2A (p16) and CDKN1A (p21), which are frequently epigenetically silenced in cancer. We confirmed that both TSP1 and CDKN2A have abnormal promoter region DNA methylation in primary melanoma, but the mechanism by which this silencing occurs remains unknown. Here we explore the effects of stable lentiviral Id1 overexpression on the expression of these Id1 target genes in human melanoma cell lines. Overexpressed Id1 was functional and bound transcriptional activator E2A, but did not sequester E2A from gene promoters and repress gene expression. Therefore, these Id1 target genes were resistant to Id1-mediated gene silencing. Our results suggest that Id1 activation may need to occur at discrete stages in cooperation with additional gene dysregulation to repress and induce epigenetic silencing of tumor suppressor genes during melanoma progression.

Granulomatous rosacea and Crohn's disease in a patient homozygous for the Crohn-associated NOD2/CARD15 polymorphism R702W

NOD2/CARD15 belongs to the N-terminal caspase recruitment domain family of proteins involved in regulating NF-kB activation in response to inflammatory stimuli transduced through Toll-like receptors. Mutations and polymorphisms in the NOD2/CARD15 gene reduce antibacterial responses and are associated with granulomatous inflammatory conditions such as Blau syndrome and early-onset sarcoidosis. The polymorphism R702W (arginine to tryptophan) is strongly associated with susceptibility to Crohn's disease in Caucasian populations. Skin abnormalities (other than cutaneous manifestations of Crohn's disease) have not been previously associated with R702W. We report on a female patient homozygous for R702W who developed granulomatous rosacea at the age of 12 years old. From the occurrence in the context of Crohn associated with R702W, we speculate that granulomatous rosacea may be an entity distinct from other forms of rosacea, which are associated with increased production of antibacterial proteins such as cathelicidin.

Leukocyte infiltration and tumor cell plasticity are parameters of aggressiveness in primary cutaneous melanoma

Various clinical and experimental observations detected an immunological host defense in cutaneous melanoma. In order to investigate the prognostic value of leukocyte effector mechanisms, we examined the presence of different subsets of leukocytes in tumor samples of 58 patients diagnosed with primary cutaneous melanoma. The presence of T lymphocytes, cytotoxic T lymphocytes, B lymphocytes, CD16+ cells and macrophages was correlated to Breslow depth. A significantly higher amount of several subsets of leukocytes was found in samples with a more progressed tumor stage and survival analysis demonstrated that a higher amount of T lymphocytes and CD16+ cells was associated with a short survival. The amount of FOXP3+ regulatory T lymphocytes did not correlate with survival, nevertheless, it correlated with the amount of total infiltrate. In contrast, analysis of the expression of CD69, a marker for activated lymphocytes, demonstrated that patients with a higher amount of CD69+ lymphocytes had a better survival. In addition, a new parameter for aggressiveness of melanoma, tumor cell plasticity [i.e., the presence of periodic acid Schiff's (PAS) reagent positive loops], also predicted short survival and a trend of a higher amount of tumor infiltrating leukocytes in tumors with PAS positive loops was observed. These findings demonstrate that leukocyte infiltration and the presence of PAS loops is a sign of tumor aggressiveness and may have prognostic value.

High expression of DNA repair pathways is associated with metastasis in melanoma patients

We have identified a gene-profile signature for human primary malignant melanoma associated with metastasis to distant sites and poor prognosis. We analyse the differential gene expression by looking at whole biological pathways rather than individual genes. Among the most significant pathways associated with progression to metastasis, we found the DNA replication (P=10(-14)) and the DNA repair pathways (P=10(-16)). We concentrated our analysis on DNA repair and found that 48 genes of this category, among a list of 234 genes, are associated with metastatic progression. These genes belong essentially to the pathways allowing recovery of stalled replication forks due to spontaneous blockage or induced DNA lesions. Because almost all these differentially expressed repair genes were overexpressed in primary tumors with bad prognosis, we speculate that primary melanoma cells that will metastasize try to replicate in a fast and error-free mode. In contrast to the progression from melanocytes to primary melanoma, genetic stability appears to be necessary for a melanoma cell to give rise to distant metastasis. This overexpression of repair genes explains nicely the extraordinary resistance of metastatic melanoma to chemo- and radio-therapy. Our results may open a new avenue for the discovery of drugs active on human metastatic melanoma.

Gene expression profiling of primary cutaneous melanoma

Cutaneous Malignant Melanoma (CMM) is the most malignant skin tumour in humans, the incidence of which is rising rapidly in most fair-skinned populations, without apparent decline in mortality. Both hereditary, constitutional and environmental factors play a role in its etiology. CMM arises from melanocytes in the epidermis, and proceeds through discrete steps of tumor-progression that consist histologically of the radial growth phase (RGP), vertical growth phase (VGP) and metastatic phase. The underlying molecular mechanisms that govern the transition between these growth phases are hardly known. The prognosis of patients with VGP melanoma depends on several clinical and histological parameters; the latter include thickness, mitotic activity, presence or absence of ulceration and regression, and pattern of lymphocytic host response. However, there is still need for new prognostic parameters. To obtain insight in the molecular mechanisms of tumor progression in CMM, and in search of new prognostic markers, we performed global gene-expression profiling using 44K oligonucleotide micro-arrays on a unique retrospective series of 83 frozen primary MM with VGP, 9 metastases and 23 benign nevi. Unsupervised analysis allowed us o identify clusters of melanoma patients with different outcome based on their gene expression profile only. Supervised analysis resulted in the identification of a genomic signature of 254 genes with prognostic significance. The large majority of the 254 enes was correlated with thickness, thereby stressing the importance of thickness in he prognosis of CMM. This signature was validated on a separate series of melanoma patients, and proved to have a predictive accuracy comparable to what can be obtained by tumour thickness and ulceration. On an immunohistochemical level, we identified 8 new markers that may help in the prognostication of melanoma patients; three of these markers, i.e. the mini-chromosome maintenance (mcm) proteins mcm3, 4 and 6, hat are involved in DNA-replication, had independent prognostic value. Additionally, upervised analysis showed similarities in gene expression profile between primary CMM and their metastases. In conclusion, our data provide new information regarding the molecules that are operative in the progression of CMM. CMM is notorious for its resistance to chemotherapy, and disseminated CMM is a uniformly fatal disease. As several of the progression-related genes, encode molecules that have been the target of established or xperimental cancer therapies, our results may hopefully contribute to the treatment of end-stage CMM-patients.

Expression and possible role of hPTTG1/securin in cutaneous malignant melanoma

Human pituitary tumour-transforming gene 1 or hPTTG1 is a proto-oncogene that codes for securin, a protein involved in sister chromatid separation. Based on previous microarray data, we studied the expression of hPTTG1/securin in melanocytic lesions. In contrast to nevi and radial growth phase melanomas, securin was expressed by scattered cells in the vertical growth phase, suggesting a role in tumour progression. In a series of 29 nodular and 29 superficial spreading melanomas, matched for all histological prognostic parameters, securin expression was significantly correlated with the nodular subtype (P=0.018) and not related to thickness. In other cancers, hPTTG1 is involved in various oncogenic pathways, including induction of neovascularisation and aneuploidy, and inhibition of p53 activity. We found coexpression of securin with wild-type p53 in the same neoplastic cells in a minority of melanomas. Expression of securin was significantly correlated with the extent of aneuploidy but not with basic fibroblast growth factor immunoreactivity or microvessel density. DNA cytometry revealed that nuclei-overexpressing securin frequently showed tetraploidy or aneuploidy. Our data show that hPTTG1 is frequently overexpressed in nodular melanoma, and suggest that hPTTG1 may act as an oncogene in the vertical growth phase, either by inhibiting anaphase, thereby causing aneuploidy and genomic instability, or by modulating the function of p53, thereby impairing apoptosis.

Gene expression profiling of primary cutaneous melanoma: Expression of replication origins firing genes predicts clinical outcome

8024

Background: Gene-expression profiling in human cutaneous melanomas is impaired by the difficulty in getting access to a retrospective collection of frozen tumors. Thus, compared to other tumors, gene expression profiling data on human cutaneous melanomas are scarce, and data with prognostic implication are entirely lacking. In order to better understand the progression of this tumor and to identify key genes involved in melanoma prognosis, we correlated gene-expression profiles with clinical outcome in a cohort of 83 patients with primary melanoma. Methods: A class comparison and class prediction analysis was performed to identify genes able to predict 4-years. distant metastasis free-survival in 58 primary melanomas with at least 4-years follow-up or intercurrent distant metastasis or death. Results were also validated at the protein level in an independent population of 176 primary melanomas with a median clinical follow-up of 8.5 years. Results: We identified a set of sequences discriminating between primary melanomas associated with good and poor prognosis. Some of these sequences correspond to key-genes in the regulation of replication origins firing, such as mini-chromosome maintenance genes and geminin. The prognostic value of overexpression of replication origins firing genes is independent from thickness, ulceration, age and sex. Conclusions: This study has identified key-genes associated with in vivo metastatic dissemination of cutaneous melanomas. Some of our data provide new diagnostic tools for the accurate diagnosis of melanoma and shed new light on the molecular mechanisms underlying poor prognosis in melanoma patients. As some of these molecules are currently under study as targets for therapy, our data can have significant impact on the development of new melanoma therapies.

No significant financial relationships to disclose.

Gene expression profiling of primary cutaneous melanoma and clinical outcome

BACKGROUND

Gene expression profiling data for human primary cutaneous melanomas are scarce because of the lack of retrospective collections of frozen tumors. To identify differentially expressed genes that may be involved in melanoma progression and prognosis, we investigated the relationship between gene expression profiles and clinical outcome in a cohort of patients with primary melanoma.

METHODS

Labeled complementary RNA (cRNA) from each tissue sample was hybridized to a pangenomic 44K 60-mer oligonucleotide microarray. Class comparison and class prediction analyses were performed to identify genes whose expression in primary melanomas was associated with 4-year distant metastasis-free survival among 58 patients with at least 4 years of follow-up, distant metastasis, or death. Results were validated immunohistochemically at the protein level in 176 independent primary melanomas from patients with a median clinical follow-up of 8.5 years. Survival was analyzed with a Cox multivariable model and stratified log-rank test. All statistical tests were two-sided.

RESULTS

We identified 254 genes that were associated with distant metastasis-free survival of patients with primary melanoma. These 254 genes include genes involved in activating DNA replication origins, such as minichromosome maintenance genes and geminin. Twenty-three of these genes were studied at the protein level; expression of five (MCM4, P = .002; MCM3, P = .030; MCM6, P = .004; KPNA2, P = .021; and geminin, P = .004) was statistically significantly associated with overall survival in the validation set. In a multivariable Cox model adjusted for tumor thickness, ulceration, age, and sex, expression of MCM4 (hazard ratio [HR] of death = 4.04, 95% confidence interval [CI] = 1.39 to 11.76; P = .010) and MCM6 (HR of death = 7.42, 95% CI = 1.99 to 27.64; P = .003) proteins was still statistically significantly associated with overall survival.

CONCLUSION

We identified 254 genes whose expression was associated with metastatic dissemination of cutaneous melanomas. These genes may shed light on the molecular mechanisms underlying poor prognosis in melanoma patients.

Immunophenotype and possible origin of nevi with phenotypical heterogeneity

Biphenotypical nevi or nevi with phenotypical heterogeneity consist of phenotypically different cell populations in a pattern other than that observed in classical combined nevi or in various maturation stages of banal nevocellular nevi. Besides several well-known entities such as deep penetrating nevi and plexiform spindle cell nevi, this category of pigment cell lesions also harbors fewer delineated lesions such as nevi with atypical dermal nodules (N-ADN) and nevi with a focal atypical epithelioid cell component (N-FAECC). Their worrisome histology may result in a wrong diagnosis of malignancy. In order to discriminate them from malignant melanoma and to shed light on their histogenesis, we analyzed the immunophenotypical profile of 33 N-FAECC, 6 N-ADN, and 10 giant congenital nevi removed shortly after birth, using antibodies directed to S100 protein, gp100, tyrosinase, NKI-C3, Melan-A and Mib-1. In N-FAECC and N-ADN, the large polygonal cells expressed gp100, S100 protein and Melan-A, and reacted with monoclonal antibody NKI-C3. In addition, there was intense tyrosinase expression but no Mib-1 immunoreactivity. Unexpectedly, we observed similar single or clustered, large epithelioid cells in three out of ten giant congenital nevi; these cells showed a similar phenotype to those observed in N-ADN and N-FAECC. Our histological and immunohistochemical data suggest that N-FAECC and N-ADN may reflect different stages of the same disorder. Moreover, their resemblance to the large polygonal cells in congenital nevi may suggest that the histogenesis of N-ADN and N-FAECC may be related to the persistence and expansion of large epithelioid cells in congenital nevi shortly after birth.

Are carcinomas of the cardia oesophageal or gastric adenocarcinomas?

There is a clear relationship between Barrett's oesophagus and oesophageal adenocarcinoma, and between Helicobacter pylori and gastric cancer, but the histogenesis of cardiac adenocarcinomas is unknown. Some clues as to possible disease associations may be provided by the pattern of gastritis. In our study, we analysed gastritis associated with oesophageal, cardiac and gastric adenocarcinomas according to the Sydney classification. Chronic gastritis was more common in gastric (88%) than in cardiac (56%) and oesophageal adenocarcinomas (38%). H. pylori was significantly more prevalent in gastric (73%) than in cardiac (34%) or oesophageal (21%) adenocarcinomas. Our results show that factors other than H. pylori must be involved in the histogenesis of cardiac adenocarcinomas. As the pattern of gastritis and the clinical features of cardiac adenocarcinomas are more comparable to oesophageal carcinomas than gastric carcinomas, we speculate that most of these tumours share similar aetiological factors with oesophageal carcinomas.

New Phenotypical and Ultrastructural Findings in Spindle Cell (Desmoplastic/Neurotropic) Melanoma

Spindle cell melanoma is a rare and distinctive variant of malignant melanoma that is composed of spindled neoplastic cells and includes desmoplastic and neurotropic melanoma. The lack of expression of several melanoma markers may result in a delayed or wrong diagnosis. In this study, we have analyzed in detail the phenotype of the tumor cells in 9 spindle cell melanomas on both paraffin-embedded and frozen material, using melanocytic, neural, and mesenchymal markers. The neoplastic cells expressed the melanocytic markers S-100, Mel-CAM, and NKIC3, but lacked gp100 and Melan-A; tyrosinase and c-Kit were expressed in 2 of 7 cases. Most cases expressed the neural markers p75-nerve growth factor receptor, neural cell adhesion molecule, and NSE. All cases expressed vimentin but lacked the mesenchymal markers CD34 and alpha-smooth muscle actin. Remarkably, all spindle cell melanomas strongly and diffusely expressed the fibroblastic markers Thy1 (CD90) and aminopeptidase N (CD13) and variably expressed the enzyme prolyl-4-hydroxylase, involved in procollagen formation. The coexpression of melanocytic, neural, and fibroblastic markers suggests bidirectional differentiation of neoplastic melanocytes toward (myo)fibroblasts and Schwann cells, a feature that was confirmed by electron microscopy. Furthermore, the lack of CD90 and CD13 staining in a wide range of melanocytic lesions suggests specificity of these markers for spindle cell melanoma.

Aneurysmal bone cyst of the nose with 17p13 involvement

We report on a 6-year-old girl with a polypoid mass, filling up the entire right nasal cavity as shown on a magnetic resonance imaging scan. Histologically, the tumor had the characteristics of an aneurysmal bone cyst, which is extremely rare in this location. Cytogenetic analysis disclosed a single (6:17)(p21;p13) translocation, confirming a specific genetic involvement in the development of aneurysmal bone cysts. Fluorescent in situ hybridization analysis mapped the putative gene between the p53 (17p13.1) and the Mieller-Dieker gene (17p13.3) loci.

Calcifying/ossifying synovial sarcoma shows t(X;18) with SSX2 involvement and mitochondrial calcifications

AIMS

Synovial sarcoma with extensive calcification and ossification is a rare variant, the ultrastructural, cytogenetic and molecular analysis of which has not been reported previously.

METHODS AND RESULTS

A large mass in the shoulder of a 20-year-old male patient led to a deformity of the chest wall, thus supporting the hypothesis that this is a slowly growing variant of synovial sarcoma. Nevertheless, the patient developed metastatic lung disease 7 months after resection. On histology, the monophasic spindle cell proliferation was in several areas obscured by the massive calcification and ossification. Immunohistochemistry showed keratin, epithelial membrane antigen, vimentin and CD99 expression. The cytogenetic analysis revealed a single t(X;18)(p11.2; q11.2), typical for synovial sarcoma. Additional fluorescence in-situ hybridization revealed SSX2 involvement. At the ultrastructural level, prominent needle-shaped intramitochondrial crystals were present, both in the cytoplasm and in the extracellular matrix.

CONCLUSION

The presence of the t(X;18) with SSX2 involvement definitively characterizes this tumour as a variant of synovial sarcoma. In addition, the needle-like mitochondrial calcifications give a possible clue to the pathogenesis of the extensive metaplastic ossification and calcification.