Krzysztof T. Drzewiecki

Spontaneous regression of metastases from melanoma: review of the literature.

Regression of metastatic melanoma is a rare event, and review of the literature reveals a total of 76 reported cases since 1866. The proposed mechanisms include immunologic, endocrine, inflammatory and metastatic tumour nutritional factors. We conclude from this review that although the precise mechanisms remain unknown, some event must trigger the immune system to produce a stronger than normal response that results in regression of the melanoma metastases. Immunologic studies of patients with regression may disclose the underlying mechanisms and lead to new therapies of disseminated melanoma.

EANM-EORTC general recommendations for sentinel node diagnostics in melanoma

The accurate diagnosis of a sentinel node in melanoma includes a sequence of procedures from different medical specialities (nuclear medicine, surgery, oncology, and pathology). The items covered are presented in 11 sections and a reference list: (1) definition of a sentinel node, (2) clinical indications, (3) radiopharmaceuticals and activity injected, (4) dosimetry, (5) injection technique, (6) image acquisition and interpretation, (7) report and display, (8) use of dye, (9) gamma probe detection, (10) surgical techniques in sentinel node biopsy, and (11) pathological evaluation of melanoma-draining sentinel lymph nodes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to “general consensus” and similar expressions. The recommendations are designed to assist in the practice of referral to, performance, interpretation and reporting of all steps of the sentinel node procedure in the hope of setting state-of-the-art standards for good-quality evaluation of possible spread to the lymphatic system in intermediate-to-high risk melanoma without clinical signs of dissemination.

2-cm versus 4-cm surgical excision margins for primary cutaneous melanoma thicker than 2 mm: a randomised, multicentre trial

BACKGROUND Optimum surgical resection margins for patients with clinical stage IIA-C cutaneous melanoma thicker than 2 mm are controversial. The aim of the study was to test whether survival was different for a wide local excision margin of 2 cm compared with a 4-cm excision margin. METHODS We undertook a randomised controlled trial in nine European centres. Patients with cutaneous melanoma thicker than 2 mm, at clinical stage IIA-C, were allocated to have either a 2-cm or a 4-cm surgical resection margin. Patients were randomised in a 1:1 allocation to one of the two groups and stratified by geographic region. Randomisation was done by sealed envelope or by computer generated lists with permuted blocks. Our primary endpoint was overall survival. The trial was not masked at any stage. Analyses were by intention to treat. Adverse events were not systematically recorded. The study is registered with ClinicalTrials.gov, number NCT01183936. FINDINGS 936 patients were enrolled from Jan 22, 1992, to May 19, 2004; 465 were randomly allocated to treatment with a 2-cm resection margin, and 471 to receive treatment with a 4-cm resection margin. One patient in each group was lost to follow-up but included in the analysis. After a median follow-up of 6·7 years (IQR 4·3-9·5) 181 patients in the 2-cm margin group and 177 in the 4-cm group had died (hazard ratio 1·05, 95% CI 0·85-1·29; p=0.64). 5-year overall survival was 65% (95% CI 60-70) [corrected] in the 2-cm group and 65% (40-70) in the 4-cm group (p=0·69). INTERPRETATION Our findings suggest that a 2-cm resection margin is sufficient and safe for patients with cutaneous melanoma thicker than 2 mm. FUNDING Swedish Cancer Society and Stockholm Cancer Society.

MicroRNA Expression in Melanocytic Nevi: The Usefulness of Formalin-Fixed, Paraffin-Embedded Material for miRNA Microarray Profiling

MicroRNAs (miRNAs) are small, noncoding RNA molecules that regulate cellular differentiation, proliferation, and apoptosis. MiRNAs are expressed in a developmentally regulated and tissue-specific manner. Aberrant expression may contribute to pathological processes such as cancer, and miRNA may therefore serve as biomarkers that may be useful in a clinical environment for diagnosis of various diseases. Most miRNA profiling studies have used fresh tissue samples. However, in some types of cancer, including malignant melanoma, fresh material is difficult to obtain from primary tumors, and most surgical specimens are formalin fixed and paraffin embedded (FFPE). To explore whether FFPE material would be suitable for miRNA profiling in melanocytic lesions, we compared miRNA expression patterns in FFPE versus fresh frozen samples, obtained from 15 human melanocytic nevi. Out of microarray data, we identified 84 miRNAs that were expressed in both types of samples and represented an miRNA profile of melanocytic nevi. Our results showed a high correlation in miRNA expression (Spearman r-value of 0.80) between paired FFPE and fresh frozen material. The data were further validated by quantitative RT-PCR. In conclusion, FFPE specimens of melanocytic lesions are suitable as a source for miRNA microarray profiling.

A cryptic BAP1 splice mutation in a family with uveal and cutaneous melanoma, and paraganglioma

Inactivating germ line BRCA1‐associated protein‐1 (BAP1) mutations have recently been reported in families with uveal or cutaneous malignant melanoma (UMM, CMM), mesothelioma, and meningioma. Although apparently predisposing to a wide range of tumors, the exact tumor spectrum associated with germ line BAP1 mutations has yet to be established. Here, we report a novel germ line BAP1 splice mutation, c.1708C>G (p.Leu570fs*40), in a multiple‐case Danish UMM family with a spectrum of other tumors. Whole‐exome sequencing identified an apparent missense mutation of BAP1 in UMM, CMM, as well as paraganglioma, breast cancer, and suspected mesothelioma cases in the family. Bioinformatic analysis and splicing assays demonstrated that this mutation creates a strong cryptic splice donor, resulting in aberrant splicing and a truncating frameshift of the BAP1 transcript. Somatic loss of the wild‐type allele was also confirmed in the UMM and paraganglioma tumors. Our findings further support BAP1 as a melanoma susceptibility gene and extend the potential predisposition spectrum to paraganglioma.

Downregulation of miR-125b in metastatic cutaneous malignant melanoma.

This study aimed to identify microRNA species involved in the earliest metastatic event in cutaneous malignant melanoma (MM). Samples from 28 patients with MM [stage T2 (tumor), M0 (distant metastasis)] were grouped by the presence of micrometastasis in the sentinel lymph nodes (N0/N1). Melanoma cells were harvested from primary, cutaneous MM tumors by laser-capture microdissection, and microRNA expression profiles were obtained by the microarray technique. Results were validated by quantitative reverse transcription PCR. We found that miR-125b was downregulated in the primary cutaneous melanomas that produced early metastases (T2, N1, M0) compared with the sentinel lymph node-negative (T2, N0, M0) melanomas. MiR-125b has earlier been found to be downregulated in other tumor types and in atypic naevi compared with the common acquired naevi. In conclusion, miR-125b may be involved in an early progression of cutaneous MM.

Eye and hair colour, skin type and constitutive skin pigmentation as risk factors for basal cell carcinoma and cutaneous malignant melanoma. A Danish case-control study.

To assess the importance of hair and eye colour, skin type and constitutive skin pigmentation as risk factors for basal cell carcinoma and cutaneous malignant melanoma in fair-skinned Caucasians, we conducted two identical case-control studies in Denmark. We studied 145 cases with basal cell carcinoma and 174 matched controls, and 168 cases with cutaneous malignant melanoma and 176 matched controls. Controls were matched on age, gender and place of residence. Subjects indicated their hair colour before 7 years of age, and at 25 years of age and their skin phototype. Interviewers assessed the present hair colour and eye colour, and the constitutive skin pigmentation was measured objectively by skin reflectance of UV unexposed buttock skin. There were no differences between basal cell carcinoma cases and controls in hair colour or eye colour or constitutive skin pigmentation, but more cases were of skin type II than skin type IV; skin type 11 was a risk factor for basal cell carcinoma with an odds ratio (OR) of 2.3. For cutaneous malignant melanoma, more cases than controls were red-haired or blond and of skin type II, but there was no difference in constitutive skin pigmentation. Hair colour and skin type were found to be independent risk factors for cutaneous malignant melanoma; red hair vs. black/brown: OR >9.7, blond hair vs. brown/black: OR = 2.4, and skin type 11 vs. type IV: OR=2.0. There were no gender-related differences in risk factors for basal cell carcinoma and cutaneous malignant melanoma.

MicroRNA miR-125b induces senescence in human melanoma cells.

MicroRNAs (miRNAs) are small noncoding RNA molecules involved in gene regulation. Aberrant expression of miRNA has been associated with the development or progression of several diseases, including cancer. In a previous study, we found that the expression of miRNA-125b (miR-125b) was two-fold lower in malignant melanoma producing lymph node micrometastases than in nonmetastasizing tumors. To get further insight into the functional role of miR-125b, we assessed whether its overexpression or silencing affects apoptosis, proliferation, or senescence in melanoma cell lines. We showed that overexpression of miR-125b induced typical senescent cell morphology, including increased cytoplasmatic/nucleus ratio and intensive cytoplasmatic &bgr;-galactosidase expression. In contrast, inhibition of miR-125b resulted in 30–35% decreased levels of spontaneous apoptosis. We propose that downregulation of miR-125b in an early cutaneous malignant melanoma can contribute to the increased metastatic capability of this tumor.

Immunohistological analysis of the lymphoid infiltrate in cutaneous malignant melanomas

The immunological phenotypes of the lymphoid cells in 39 cutaneous malignant melanomas have been investigated by staining cryostat sections with a panel of 20 monoclonal antibodies against lymphoid cells and their subsets. Staining was performed by the alkaline phosphatase: anti-alkaline phosphatase (APAAP) method in which the substrate label (red) is easily distinguishable from melanin. The lymphoid infiltrates had an essentially identical composition in all cases, consisting of T-lymphocytes associated with both Langerhans cells and HLA-DR-positive tissue macrophages. B-lymphocytes and natural killer cells were either absent or only present in low numbers. The ratio between T8 (suppressor/cytotoxic) and T4 (helper/inducer) lymphocytes varied and showed no correlation with melanoma subtype, level of invasion or magnitude of lymphocytic response. Examination for markers associated with T-cell activation and/or with cell proliferation revealed that all lesions contained HLA-DR-positive T-lymphocytes, whereas expression of the transferrin receptor and the interleukin-2 receptor (Tac-antigen) occurred mainly in melanomas with a significant inflammatory infiltrate. These data support the concept that malignant melanomas are capable of evoking autologous T-cell immune reactions.

Sentinel node biopsy for melanoma: a study of 241 patients.

The aim of this study was to evaluate the sentinel node biopsy (SNB) technique for melanoma using both radiocolloid and blue dye in 241 clinically N0 patients with melanomas >1.0 mm, or thinner lesions exhibiting regression/ulceration. We showed that an increase in injected radioactivity increased both the number of visualized nodes at lymphoscintigraphy and the number of SNs removed surgically. At least one SN was removed in 98% (236) of patients, and all nodes were identified with the probe. Seventy-four per cent of the 194 patients injected with blue dye had stained SNs. In 46% (144) of the lymph node basins, there was a discrepancy between the nodes visualized at lymphoscintigraphy and the nodes removed at surgery. There were 38 unusually located nodes. Only eight of these were removed surgically; none contained metastases. SN metastases were detected in 22% (53) of patients. There were nine haematoxylin and eosin (HE)-negatives, all of which were found by immunohistochemistry. The false negative rate for the SNB procedure was 4% (2/55). The complication rate was 6% after SNB and 29% after complete node dissection. In conclusion, SN status is a strong prognostic factor in melanoma patients, and SNB has made the approach to radical lymphadenectomy more rational.