Peter Helmbold

Hidradenitis suppurativa (acne inversa): early inflammatory events at terminal follicles and at interfollicular epidermis*

Please cite this paper as: Hidradenitis suppurativa (acne inversa): early inflammatory events at terminal follicles and at interfollicular epidermis. Experimental Dermatology 2010; 19: 533–537.

Frequent hypermethylation of RASSF1A tumour suppressor gene promoter and presence of Merkel cell polyomavirus in small cell lung cancer

In small cell lung cancer (SCLC), hypermethylation of the tumour suppressor Ras association domain family 1A (RASSF1A) is frequent. It is associated with SV40 polyomaviral infection in other tumours. Merkel cell polyomavirus (MCPyV) infection has been reported in Merkel cell carcinoma (MCC), a neuroendocrine carcinoma with biological similarity to SCLC. In our study, we investigated polyomavirus infection (SV40 and MCPyV) and promoter hypermethylation of the tumour suppressors RASSF1A and p16 in 18 SCLCs (14 primaries and 4 regional lymph node metastases) and 18 blood control samples. MCPyV was found in 39% (7 of 18) of the tumour tissues but not observed in controls. SV40 was not observed in the tumour tissue. RASSF1A promoter hypermethylation (94%; 17 of 18) was more frequent compared to p16 methylation (56%, 10 of 18). We found no significant correlation between RASSF1A or p16 promoter hypermethylation and infection with the investigated polyoma viruses. Our results show a high frequency of hypermethylation of the RASSF1A promoter and occurrence of MCPyV infection in the tumour tissue of SCLC. These events may contribute to the pathogenesis of SCLC.

Methylation of PTEN as a Prognostic Factor in Malignant Melanoma of the Skin

the same DNA extract. Thus far, it is recognized that a mutation in either NRAS or BRAF is sufficient for activation of the Ras–Raf–MEK–ERK pathway, with mutant RAS having a 50-fold higher activation effect than mutant BRAF (Davies et al., 2002). Although we do not have any evidence that the NRAS and BRAF mutations found in the same DNA extract were coexisting in the same cells, it is possible that the L32P mutation in CDKN2A somehow permits cellular tolerance of these dual mutations. In conclusion, the NRAS and BRAF mutation rates we observed in familial melanomas were generally lower than those in most previous reports in sporadic melanoma but equal to those reported for primary melanomas of similar thickness (Shinozaki et al., 2004; Goel et al., 2006). Samples that harbored INK4A L32P substitutions also had a high frequency of coexisting mutations in both NRAS and BRAF. This suggests that in some instances constitutional CDKN2A mutations affect the occurrence of somatic mutations in NRAS and BRAF, although further research is needed to substantiate this hypothesis.

Frequent occurrence of RASSF1A promoter hypermethylation and Merkel cell polyomavirus in Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is one of the most aggressive cancers of the skin. It has recently been reported that integration of a Merkel cell polyomavirus (MCPyV) in receptor tyrosine phosphates type G (PTPRG) gene occurs in MCC, and that viral infections are associated with epigenetic silencing of tumor suppressor genes (TSG) in cancer. To examine whether a correlation between TSG inactivation and viral infection can be found in MCC, we investigated the promoter hypermethylation of RASSF1A, TP73, PTPRG, FHIT, and CDKN2A and the presence of MCPyV and SV40 in 98 MCC by PCR. Hypermethylation of RASSF1A was frequently found in 42 of 83 (51%) of MCC. Methylation of CDKN2A was present in 9 of 41 (22%) of MCC. Hypermethylation of TP73 (0%), PTPRG (4%), and FHIT (0%) was infrequent in MCC. Interestingly, MCPyV was found in 90 of 98 (92%) MCC, however, no SV40 signal was detected. No correlation between TSG hypermethylation and viral infection was found. Our results show frequent hypermethylation of RASSF1A and the presence of MCPyV in primary MCC, and that these events may contribute to the pathogenesis of MCC.

Neoadjuvant Imatinib in Advanced Primary or Locally Recurrent Dermatofibrosarcoma Protuberans: A Multicenter Phase II DeCOG Trial with Long-term Follow-up

Purpose: Dermatofibrosarcoma protuberans (DFSP) is a rare cutaneous tumor. COL1A1–PDGFB gene fusion is frequent in DFSP, rendering tumor cell proliferation and survival dependent on PDGFRβ (platelet-derived growth factor receptor β) signaling. This trial investigated imatinib as neoadjuvant treatment of DFSP, including long-term follow-up. Experimental Design: The primary endpoint of this multicenter phase II trial was response; secondary endpoints were safety, tumor relapse, and response biomarkers. Patients with advanced primary or locally recurrent DFSP and measurable disease by RECIST (response evaluation criteria in solid tumors) were eligible and received imatinib 600 mg/d until definitive surgery with histopathologic proof of tumor-free margins. Results: Sixteen patients received imatinib, and 14 patients were evaluable for all endpoints. Median treatment duration was 3.1 months; median tumor shrinkage was 31.5%. Best overall response was 7.1% complete response (CR), 50.0% partial response (PR), 35.7% stable disease, and 7.1% progressive disease (PD). Toxicity was moderate with 25.0% grade 3 and 4 events. During a median follow-up of 6.4 years, one patient developed secondary resistance to imatinib but responded to second-line sunitinib. This patient also presented local recurrence, distant metastasis, and death from DFSP. Exploratory analysis showed that response to imatinib was associated with decreased tumor cellularity and formation of strong hyalinic fibrosis. Weak PDGFRB phosphorylation and pigmented-type DFSP were associated with nonresponse. Additional to PDGFRB, the kinases EGFR and insulin receptor were found activated in a high percentage of DFSPs. Conclusion: The neoadjuvant use of imatinib 600 mg/d in DFSP is efficacious and well tolerated. Long-term follow-up results do not definitely support smaller surgical margins after successful imatinib pretreatment, and presume that secondary resistance to imatinib might promote accelerated disease progression. Clin Cancer Res; 20(2); 499–510. ©2013 AACR.

Hyperplasia of dermal microvascular pericytes in scleroderma

Background:  Pericytes (PCs) are smooth muscle‐like mural cells of capillaries and venules, which can synthesize matrix components and fibroblast‐activating cytokines, and are thus potential mediators of pathological changes in scleroderma. In this study, alterations in microvessels were quantitatively imaged, taking PC into account for the first time.

Concomitant traumas influence prognosis in melanomas of the nail apparatus

Background  In nail apparatus melanomas (NAM), the role of standard melanoma prognostic factors is under discussion. The prognostic influence of traumas to the clinically apparent tumour has not been sufficiently examined.

Palliative total skin electron beam therapy (TSEBT) for advanced cutaneous T-cell lymphoma

Our aim was to analyze the effectiveness of palliative total skin electron beam therapy (TSEBT) in the management of advanced cutaneous T-cell non-Hodgkins lymphoma (CTCL). Eighteen patients (median age 59 years) with advanced and therapy-refractory CTCL in stages IIB-IV were treated with TSEBT for the first time. The most common histological subtype was Mycosis fungoides (72%). All patients suffered from lymphoma-associated symptoms. Median daily fractions of 1 Gy were administered up to a median total dose of 25 Gy. The median follow-up period was 11 months. Nine patients (50%) achieved a complete response and seven patients (39%) had a limited response. The actuarial one-year progression-free survival was 24%. Four patients (22%) had continuing remission over a median period of six months. Lymphoma associated symptoms were improved in 16 patients (89%). The median overall survival after receiving TSEBT was 12 months, resulting in an actuarial one-year overall survival of 48%. Treatment related acute effects (grade 1 or 2) were observed in all patients during radiation therapy. Transient grade 3 epitheliolyses developed in five patients (28%), late skin effects (grade 1 and 2) in 16 patients (89%), and hypohidrosis was seen in six patients (33%). We conclude that TSEBT is a very efficient and tolerable palliative treatment for patients with advanced CTCL.

RASSF10 Promoter Hypermethylation Is Frequent in Malignant Melanoma of the Skin but Uncommon in Nevus Cell Nevi

The Ras association domain family (RASSF) consists of several tumor suppressor genes, which are frequently silenced in human cancers. We analyzed the epigenetic inactivation of RASSF2 and RASSF10 in malignant melanoma (MM) of the skin, including 5 MM cell lines, 28 primary MM, 33 metastases of MM, 47 nevus cell nevi (NCN), and 22 control tissues. The RASSF2 promoter was epigenetically downregulated in two MM cell lines only, but not in any of the investigated tumor samples. In contrast, hypermethylation of the RASSF10 promoter was found in all investigated cell lines, 19/28 (68%) of the primary MM and 30/33 (91%) of the MM metastases, 2/18 (11%) of the dysplastic NCN, and 0/29 (0%) of the non-dysplastic NCN (difference between MM and all nevi, P<0.001). RASSF10 promoter hypermethylation correlated with a reduced RASSF10 mRNA expression in 3/4 MM cell lines, and treatment with a DNA methylation inhibitor reactivated RASSF10 transcription. Furthermore, immunohistological RASSF10 expression corresponds negatively to its promoter methylation state. In summary, RASSF10 proved to be a characteristically epigenetically silenced tumor suppressor in melanomagenesis, and analysis of RASSF10 methylation status represents a new candidate tool to assist in discrimination between MM and NCN.

Human dermal pericytes express 3G5 ganglioside--a new approach for microvessel histology in the skin.

Background: Pericytes cover the abluminal surface of microvessels and play an important role in capillary regulation and pathology. Studies on pericytes have been hindered by the lack of specific markers with which to facilitate microscopic identification of this cell type. Expression of the cell surface 3G5 ganglioside antigen has been reported in cultured retinal and cardiac pericytes. The objective of this study was to determine the usefulness of monoclonal antibody 3G5 as a pericyte marker in human skin.