MicroRNA-15b represents an independent prognostic parameter and is correlated with tumor cell proliferation and apoptosis in malignant melanoma

MicroRNAs (miRNAs) are small noncoding RNAs ( approximately 22 bp) that posttranscriptionally regulate gene expression. MiRNAs possess oncogenic or tumor suppressor activity in various tumors but little is known about miRNA expression pattern in malignant melanoma. We determined the expression level of 16 potentially relevant miRNAs (miR-15a, miR-15b, miR-16, miR-34a, miR-210, let-7I, miR-23a, miR-23b, miR-24, miR-27a, miR-27b, miR-100, miR-137, miR-222, miR-373-1, miR-373*) by real-time PCR in 6 preparations of normal melanocytes vs. 10 melanoma cell lines and in formalin fixed paraffin embedded tissue of 11 melanocytic nevi versus 16 melanomas. MiR-15b and miR-210 were significantly upregulated, miR-34a was significantly downregulated in melanomas compared with melanocytic nevi. These 3 miRNAs were analyzed in a total of 128 primary melanomas from patients with detailed clinical follow-up information. High expression of miR-15b (but not miR-210 upregulation and miR-34a downregulation) was significantly associated with poor recurrence free survival and overall survival by univariate Kaplan-Meier and multivariate Cox analyses. Downregulation of miR-15b in two melanoma cell lines with high miR-15b expression by transfection with anti-miR-15b siRNA was associated with reduced tumor cell proliferation, whereas apoptosis was increased. In summary, miRNA expression levels show distinct differences comparing benign and malignant melanocytic cell proliferations and can provide independent prognostic informations. MiR-15b appears to represent a particular important miRNA in melanoma that is associated with poor prognosis and tumorigenesis.

C-kit-positive multipolar cells in human penile erectile tissue: expression of connexin 43 and relation to trabecular smooth muscle cells

The aim of this study was to evaluate the hypothesis that interstitial cells might play a role in controlling and synchronizing via gap junctions the electrical activity of smooth muscle cells. The expression and distribution of interstitial cells in human penile erectile tissue was evaluated to determine whether or not cavernous interstitial cells express the gap junction protein connexin 43. Specimens of human corpus cavernosum were excised from full preparations of human penises. Cryostat sections (10 microm to 15 microm) of formaldehyde-fixated tissue segments were incubated using a double-labelling technique with antibodies directed against smooth muscle alpha-actin, c-kit, and connexin 43. Then, sections were exposed to secondary antibodies. Visualization was commenced by means of laser fluorescence microscopy. Double-staining techniques revealed immunosignals specific for c-kit (transmembrane receptor protein) and connexin 43 (gap junction protein) in multipolar cells located adjacent to smooth muscle cells. The number of c-kit-positive cells was significantly lower within the smooth musculature than within bundles of connective tissue surrounding smooth muscle cells of corpus cavernosum or cavernous arteries. Our findings demonstrate the distribution of c-kit- and connexin 43-positive interstitial cells in the connective tissue and smooth musculature of the corpus cavernosum. Additional studies are needed in order to evaluate further the ultrastructure of human penile erectile tissue and enable the identification of gap junctions mediating direct cell-to-cell communication.

Analysis of c-KIT expression and KIT gene mutation in human mucosal melanomas

Recent data suggested an increased frequency of KIT aberrations in mucosal melanomas, whereas c-KIT in most types of cutaneous melanomas does not appear to be of pathogenetic importance. However, studies investigating the status of the KIT gene in larger, well-characterised groups of patients with mucosal melanomas are lacking. We analysed 44 archival specimens of 39 well-characterised patients with mucosal melanomas of different locations. c-KIT protein expression was determined by immunhistochemistry, KIT gene mutations were analysed by PCR amplification and DNA sequencing of exons 9, 11, 13, 17 and 18. c-KIT protein expression could be shown in 40 out of 44 (91%) tumours in at least 10% of tumour cells. DNA sequence analysis of the KIT was successfully performed in 37 patients. In 6 out of 37 patients (16%) KIT mutations were found, five in exon 11 and one in exon 18. The presence of mutations in exon 11 correlated with a significant stronger immunohistochemical expression of c-KIT protein (P=0.015). Among the six patients with mutations, in two patients the primary tumour was located in the head/neck region, in three patients in the genitourinary tract and in one patient in the anal/rectal area. In conclusion, KIT mutations can be found in a subset of patients with mucosal melanomas irrespective of the location of the primary tumour. Our data encourage therapeutic attempts with tyrosine kinase inhibitors blocking c-KIT in these patients.

[Intravascular lymphoma: two case reports demonstrating the heterogeneity of the disease]

Intravascular lymphoma (IVL) is a rare subtype of extranodal large-B-cell lymphoma, histologically characterized by accumulation of clonal lymphocytes in small vessels of different organs. Overall survival is usually poor. The clinical manifestations are highly variable, depending on the involved organs. Cutaneous and neurological involvement is frequent; the cutaneous symptoms are heterogeneous with erythema, erythematous papules and plaques, generalized telangiectases and lesions resembling panniculitis or Kaposi sarcoma. IVL may also be limited to the skin; this entity is included the current classifications. We present here two patients with two different variants of IVL. One showed only skin involvement with panniculitis-like induration and responded well to therapy with Rituximab-CHOP (Rituximab plus Cyclophosphamide, Doxorubicin, Vincristine, Prednisolone). The other patient had distinctive cutaneous and neurological symptoms which did not respond to therapy. By means of these two patients, we present the heterogeneity of IVL and discuss current aspects of diagnosis and treatment.

Prognostic significance of isolated HMB45 or Melan A positive cells in Melanoma sentinel lymph nodes

The detection of micrometastases (defined as groups of malignant cells) in the sentinel lymph node (SLN) is an important prognostic tool in melanoma. The use of immunohistochemistry with melanocytic markers such as HMB45 and Melan A increases the detection rate of micrometastases but there are also cases with isolated immunohistochemically positive cells (IPC). To determine the prognostic significance of isolated HMB45 and/or Melan A positive cells in melanoma SLN, we compared the clinical course of 47 patients with IPC to 308 patients with negative SLN and to 122 patients with micrometastases. The mean follow-up was 38.1 months. By Kaplan-Meier analyses, relapse free survival and overall survival of patients with IPC were similar to SLN negative patients, whereas patients with micrometastases had a significantly worse relapse free survival and overall survival. In the 47 patients with IPC, 6 relapses (12.8%) and 3 melanoma-related death (6.4%) occurred, in the SLN negative patients 36 relapses (11.7%) and 17 melanoma-related deaths (5.5%), in the patients with micrometastases 46 relapses (37.7%) and 29 melanoma-related deaths (23.8%). Prognosis of patients with IPC in SLN did not correlate with type of positive staining (HMB45, Melan A, or both), capsular involvement, number of cells, presence of cytologic atypias of IPC, or tumor penetrative depth. In conclusion, with short-term follow-up IPC in melanoma SLN are without prognostic significance.

Prognostic significance of histopathological parameters in sentinel nodes of melanoma patients

AIMS

The presence of micrometastases in the sentinel lymph node (SLN) is an important prognostic parameter for melanoma patients. The aim was to determine the prognostic relevance of histopathological characteristics of micrometastases in the SLN, which has not been adequately addressed thus far.

METHODS AND RESULTS

In 169 melanoma patients with positive SLN, histopathological features of the SLN were correlated with overall survival (OS) and relapse-free survival (RFS). Tumour burden, expansion of melanoma cells in the periphery (infiltration of capsule) and towards the centre of the SLN [tumour penetrative depth (TPN)] were of prognostic significance for OS and RFS on univariate analysis. Multivariate analysis revealed three independent significant parameters which predict a poor prognosis: presence of infiltration of the SLN capsule, TPN > or = 2 mm and size of the largest tumour deposit > or = 30 cells.

CONCLUSIONS

Histopathological analysis of SLN allows the identification of patients with a poor prognosis depending on the location of melanoma cells and tumour burden.

Therapeutic use of erythropoietin in dermatooncology

Erythropoietin has been successfully used in Europe since 1997 in the treatment of anemia induced by chemotherapy of solid tumors. There is only limited experience with regard to its use when treating dermatologic tumors such as metastatic melanoma. We review here current guidelines on the use of erythropoietin in cancer patients and report on our own melanoma patients treated with erythropoietin for chemotherapy-induced anemia.

Tumoral melanosis involving the sentinel lymph nodes: a case report

Tumoral or nodular melanosis is characterized by a clinical lesion suspicious for malignant melanoma, the histopathological correlate is a nodular accumulation of melanophages in the dermis. We present a patient with nodular melanosis involving also the sentinel lymph nodes and discuss possible differential diagnoses as well as prognostic and therapeutic implications.

Autoimmunity as a prognostic factor in melanoma patients treated with adjuvant low-dose interferon alpha

Interferon alpha is used for the adjuvant treatment of malignant melanoma at different dosages (high-, intermediate-, low-dose therapy). Only a minority of patients might benefit from this therapy, and markers to identify such patients are missing. A recent study suggested that melanoma patients developing autoantibodies or clinical manifestations of autoimmunity during adjuvant high-dose interferon alpha treatment had a significant survival benefit. We retrospectively reviewed 134 melanoma patients from our institution treated with adjuvant low-dose interferon alpha therapy and correlated the development of autoimmune diseases with prognosis. Interferon (IFN) therapy was routinely monitored by history, physical examination and laboratory tests before, after the first month and then after every 3 months of therapy. During a median follow up of 46.0 months (8.5-79.0 months) 28 patients (20.9%) suffered from recurrences and melanoma related deaths occurred in 16 patients (11.9%). In 20 patients (14.9%) autoimmune thyroiditis (AIT) was diagnosed during IFN therapy, one of these 20 patients developed rheumatoid arthritis later while continuing IFN therapy. Other autoimmune diseases were not observed. In 2 patients (one with AIT and one with arthritis) the autoimmune disease led to discontinuation of IFN therapy, in the other patients AIT remained subclinical or responded well to treatment while IFN therapy was continued. Kaplan-Meier analyses revealed a significant better recurrence free survival and a trend for a better overall survival for patients with AIT. Thus, autoimmunity triggered by low-dose IFN therapy appears to indicate an improved prognosis and should encourage continuation of IFN therapy.