Detection of Merkel cell polyomavirus and human papillomaviruses in Merkel cell carcinoma combined with squamous cell carcinoma in immunocompetent European patients.

BACKGROUND: About 10% of patients with Merkel cell carcinoma (MCC) suffer from an associated squamous cell carcinoma (SCC). In European patients, Merkel cell polyomavirus (MCPyV) is detectable in 60%-88% of the MCC tumors. In combined lesions, MCPyV was not detectable so far. METHODS: We investigated 2 combined tumors of MCC and SCC for the presence of MCPyV and human papillomavirus (HPV) by polymerase chain reaction and immunohistochemistry. RESULTS: In both lesions, MCPyV DNA was found, and in 1 case, HPV DNA was also detected. This is the first report of a coinfection with HPV and MCPyV in combined MCC-SCC tumors. CONCLUSIONS: The results underline the hypothesis of co-cancerogenesis of 2 oncogenic viruses in nonmelanoma skin cancer. Technical reasons and a low viral copy number of MCPyV hampering immunohistochemical detection may be responsible for the negative results in the literature.

Merkel cell polyomavirus is present in common warts and carcinoma in situ of the skin.

Polyomaviruses have been linked to diseases of immunosuppressed patients. We sought to determine the prevalence of Merkel cell polyomavirus in benign epithelial skin neoplasms and nonmelanoma skin cancer of immunosuppressed renal transplant recipients and long-term dialysis patients. Merkel cell polyomavirus DNA was detected by polymerase chain reaction (PCR) in 2 (10%) of 20 patients, in carcinomas in situ (Bowen's disease). In one of our patients with Merkel cell polyomavirus-positive carcinoma in situ, 9 (39.1%) of 23 skin lesions at various anatomical locations tested positive for Merkel cell polyomavirus sequences by PCR, including all of his common warts (4/4), half of his carcinoma in situ lesions (3/6), and 2 of his 3 seborrheic keratoses. In a second cohort of immunosuppressed renal transplant recipients, Merkel cell polyomavirus DNA was found in 1 (6.3%) of 16 common warts and in 2 (9.5%) of 21 carcinomas in situ. In immunocompetent individuals, Merkel cell polyomavirus DNA was found in 2 (6.7%) of 30 common warts and in 2 (8.3%) of 24 carcinomas in situ. DNA of other human polyomaviruses was not detected in any of the investigated skin neoplasms. We conclude that common warts and carcinomas in situ can be positive for Merkel cell polyomavirus in immunosuppressed as well as immunocompetent individuals. Remarkably, some of the Merkel cell polyomavirus-positive common warts did not contain human papillomavirus. Furthermore, Merkel cell polyomavirus can be found in various skin neoplasms of the same individual.

Inflammatory monocytes are a reservoir for Merkel cell polyomavirus.

Merkel cell polyomavirus (MCPyV) is a recently discovered virus that is implicated in the oncogenesis of Merkel cell carcinoma (MCC). The route of dissemination and the reservoir(s) of MCPyV within the human body have not yet been identified. In this study we describe two patients with multiple MCPyV-positive inflammatory and neoplastic skin lesions at different anatomic sites. Patient 1 was suffering from psoriasis for many years and was diagnosed with MCC 7 years before this study. Patient 2 had developed numerous non-melanoma skin cancer lesions under post-transplant immunosuppression. In both patients, MCPyV DNA was detected in whole blood and in urine using PCR and direct sequencing of PCR products. When we analyzed different blood compartments, we found MCPyV exclusively in cell-free serum and in blood monocytes, but not in lymphocytes or granulocytes. Upon separate analysis of resident (CD14(lo)CD16(+)) and inflammatory (CD14(+)CD16(-)) monocytes, we detected MCPyV exclusively in inflammatory, but not in resident monocytes. Our findings raise the possibility that MCPyV persists in inflammatory monocytes and spreads along the migration routes of inflammatory monocytes. This points to intervention strategies to contain MCPyV. Moreover, blood or urine tests may serve as ancillary tests to confirm MCPyV infection in a clinical setting.

Borrelia in granuloma annulare, morphea and lichen sclerosus: a PCR-based study and review of the literature.

BACKGROUND: Morphea, granuloma annulare (GA) and lichen sclerosus et atrophicans (LSA) have also been suggested to be linked to Borrelia infection. Previous studies based on serologic data or detection of Borrelia by immunohistochemistry and polymerase chain reaction (PCR) reported contradictory results. Thus, we examined skin biopsies of morphea, GA and LSA by PCR to assess the prevalence of Borrelia DNA in an endemic area and to compare our results with data in the literature. METHODS: Amplification of DNA sequences of Borrelia burgdorferi sensu lato by nested PCR from formalin-fixed and paraffin-embedded skin biopsies of morphea, GA and LSA, followed by automated sequencing of amplification products. PCR-based studies on Borrelia species in these disorders published until July 2009 were retrieved by a literature search. RESULTS: Borrelia DNA was detected in 3 of 112 skin biopsies (2.7%) including one of 49 morphea biopsies (2.0%), one of 48 GA biopsies (2.1%) and one of 15 LSA biopsies (6.6%). Amplification products belonged to B. burgdorferi sensu stricto in two cases available for sequence analysis. CONCLUSIONS: The results of our and most of other PCR-based studies do not argue for a significant association of B. burgdorferi sensu lato with morphea, GA, LSA.

Apoptosis in CD30-positive lymphoproliferative disorders of the skin.

The spectrum of CD30-positive cutaneous lymphoproliferative disorders (CD30+ CLPD) includes lymphomatoid papulosis (LyP), primary cutaneous CD30+ large T-cell lymphoma (LTCL) and rare borderline patients. Despite their malignant histopathology, CD30+ CLPD exhibit a low-grade malignant course with an excellent prognosis and a characteristic tendency for spontaneous regression. Apoptosis of tumour cells is considered a principal mechanism of tumour regression. We examined the proliferation and apoptosis rates as well as the expression of apoptosis-related proteins in various clinical entities, tumour cell lines and evolutional (evolving and regressing) stages of CD30+ CLPD. Skin biopsies of LyP (n = 20) and LTCL (n = 19) and five CD30+ lymphoma cell lines were analysed by means of immunohistochemistry and Western blotting in order to evaluate the proliferation (Ki67), apoptosis (FragEl) and expression of Bax, Bcl-x, C-kit and Mcl-1. A significantly higher apoptotic index (AI) was found in LyP (AI = 12.5%) than in LTCL (AI = 3.1%, P < 0.005). Bax was expressed by the majority of tumour cells in all forms of CD30+ CLPD and CD30+ cell lines. However, no Bax expression was found in tumour cell lines derived from systemic CD30+ lymphomas, which lack spontaneous regression and display an aggressive clinical course. No significant correlation was found between the expression of apoptosis-related proteins and the tumour type and evolutional stage of CD30+ CLPD. We conclude that the higher AI in LyP may contribute to the regression of LyP lesions and the excellent prognosis of the disease. Pro-apoptotic protein Bax is expressed at high levels in CD30+ CLPD and may play a crucial role in mediating apoptosis of tumour cells.

Hepatitis C and G viruses in B-cell lymphomas of the skin.

BACKGROUND: The etiology of B-cell lymphoproliferative disorders (LPDs) of the skin has still to be elucidated. So far, Borrelia sp. has been identified as the causative agent of some cases of B-cell LPDs of the skin. Apart from bacterial pathogens, recent studies suggested that also flaviviruses, in particular hepatitis C (HCV) and G (HGV) viruses, may be involved in the pathogenesis of B-cell non-Hodgkin's lymphomas (NHLs). Most studies were performed in patients with known HCV infection, but the overall frequency of HCV- and HGV-RNA in tumoral tissue of primary cutaneous B-cell lymphomas (CBCLs) is unknown. METHODS: We examined 23 tumor biopsies of various forms of CBCLs by reverse transcriptase-polymerase chain reaction (RT-PCR) and sequencing for the presence of HCV and HGV. RESULTS: HCV-RNA sequences were detected in seven of 23 (30%) of the tumor biopsies. In contrast, RNA sequences of HGV were not detected in any of the tumors. CONCLUSIONS: Interestingly, the presence of HCV in our series of primary CBCLs was not restricted to a distinct clinicopathologic subform. HCV which can infect B cells, may play a role in pathogenesis of one-third of CBCLs, whereas HGV is not involved in CBCLs. Further molecular studies and therapeutic trials are needed to clarify the putative pathogenetic role of HCV in CBCLs.

Study of HHV-8 DNA sequences in archival biopsies from lesional skin of Kaposi's sarcoma, various mesenchymal tumors and related reactive conditions.

BACKGROUND: HHV-8 has been identified as the causative agent of Kaposi's sarcoma (KS) and some lymphoproliferative disorders. In addition, there are anecdotal reports on the presence of HHV-8 in other tumors, especially cutaneous epithelial and mesenchymal neoplasms. The aim of the study was to ascertain the value of identification of HHV-8 viral DNA sequences in routinely processed, formalin-fixed, paraffin-embedded tissues for the diagnosis of Kaposi's sarcoma and other mesenchymal tumors. METHODS: The presence of HHV-8 sequences in archival material was studied by nested PCR using specific primers for amplification of a 233-bp long fragment of HHV-8 (ORF 26). RESULTS: Thirty-three patients with KS (18 classic/sporadic, six post-transplant and nine AIDS-related) and various mesenchymal tumors and related conditions (n = 76) were studied. HHV-8 DNA sequences were detected in 29 of the 33 cases of KS and in one case of multiple eruptive dermatofibroma (MEDF). CONCLUSIONS: Identification of HHV-8 DNA sequences in routinely processed tissue is a useful diagnostic marker for KS. Although other mesenchymal tumors are usually not associated with HHV-8, its presence is not fully specific for KS since HHV-8 sequences were also found in one case of MEDF. Therefore, PCR analysis for the detection of HHV-8 should only be used as an additional diagnostic marker for KS and in the context of other tools such as routine histology.