Prognostic Implication of Lymphovascular Invasion Detected by Double Immunostaining for D2-40 and MITF1 in Primary Cutaneous Melanoma.

BACKGROUND Lymphovascular invasion (LVI) is associated with adverse outcomes in primary cutaneous melanoma (PCM). Detection of LVI by hematoxylin and eosin staining alone is 0%-6%, but targeting lymphovascular structures increases the detection rate. OBJECTIVE To examine the prognostic significance of LVI detected by immunostaining for D2-40 and microphthalmia-associated transcription factor 1 (MITF1) in PCM. METHODS The authors retrospectively analyzed 120 PCM samples. We compared the LVI detection rates of immunostaining for D2-40 only (22%), double staining for D2-40 and MITF1 (38%), and hematoxylin and eosin, and examined the association of LVI with clinicopathologic variables and clinical outcomes. RESULTS Immunolabeling with both methods significantly increased the LVI detection rate. Double staining for D2-40 and MITF1 as well as D2-40-detected LVI was significantly associated with increased Breslow thickness, number of mitoses, and sentinel lymph node (SLN) metastasis. D2-40-detected LVI was also associated with ulceration. Although the difference was not significant, double staining for D2-40 and MITF1 allowed for easier detection of LVI than D2-40 alone. LIMITATIONS This study was conducted in a tertiary referral institution; therefore, a referral bias cannot be excluded. CONCLUSIONS Immunolabeling increased detection of LVI in PCM. Because LVI is a positive predictive marker for SLN metastasis, the authors propose using anti-D2-40 and anti-MITF1 in the evaluation of LVI in patients with PCM with a certain risk of SLN metastasis.

Sentinel lymph node biopsy in thick malignant melanoma: A 16-year single unit experience.

BACKGROUND The role of sentinel lymph node biopsy (SLNB) and its benefits in patients with thick melanoma is still controversial. OBJECTIVES We evaluated the clinical effect of SLNB in patients with thick melanoma. METHODS We performed a retrospective cohort review (1996-2012) of thick melanomas. Collected data included the patient and tumour characteristics. Locoregional recurrence, distant metastases, disease free and overall survival were compared between the patients with positive and negative SLNB. RESULTS 126 thick melanomas with a mean age of 64.09 years were included in the study. Positive SLNB were found in 47 (37.3%) patients. Significantly more locoregional recurrence (P = 0.002) and distant metastases (P = 0.030) were detected in the patients with positive SLNB. Furthermore, the patients with negative SLNB showed significantly better disease free survival (P = 0.021). CONCLUSIONS Positive SLNB might be prognostic factor in thick melanoma and aggravates the outcome of thick melanomas.

First-in-Human Proof-of-Concept Study: Intralesional Administration of BQ788, an Endothelin Receptor B Antagonist, to Melanoma Skin Metastases

BACKGROUND This first-in-human proof-of-concept study aimed to check whether safety and preclinical results obtained by intratumoral administration of BQ788, an endothelin receptor B (EDNRB) antagonist, can be repeated in human melanoma patients. METHODS Three patients received a single intralesional BQ788 application of 3 mg. After 3-7 days, the lesions were measured and removed for analysis. The administered dose was increased to a cumulative dosage of 8 mg in patient 4 (4 × 2.0 mg, days 0-3; lesion removed on day 4) and to 10 mg in patient 5 (3 × 3.3 mg, days 0, 3, and 10; lesion removed after 14 days). Control lesions were simultaneously treated with phosphate-buffered saline (PBS). All samples were processed and analyzed without knowledge of the clinical findings. RESULTS No statistical evaluation was possible because of the number of patients (n = 5) and the variability in the mode of administration. No adverse events were observed, regardless of administered dose. All observations were in accordance with results obtained in preclinical studies. Accordingly, no difference in degree of tumor necrosis was detected between BQ788- and PBS-treated samples. In addition, both EDNRB and Ki67 showed decreased expression in patients 2 and 5 and, to a lesser extent, in patient 1. Similarly, decreased expression of EDNRB mRNA in patients 2 and 5 and of BCL2A1 and/or PARP3 in patients 2, 3, and 5 was found. Importantly, semiquantitatively scored immunohistochemistry for CD31 and CD3 revealed more blood vessels and lymphocytes, respectively, in BQ788-treated tumors of patients 2 and 4. Also, in all patients, we observed inverse correlation in expression levels between EDNRB and HIF1A. Finally, in patient 5 (the only patient treated for longer than 1 week), we observed inhibition in lesion growth, as shown by size measurement. CONCLUSION The intralesional applications of BQ788 were well tolerated and showed signs of directly and indirectly reducing the viability of melanoma cells.

Melanoma Cell-Intrinsic PD-1 Receptor Functions Promote Tumor Growth.

Therapeutic antibodies targeting programmed cell death 1 (PD-1) activate tumor-specific immunity and have shown remarkable efficacy in the treatment of melanoma. Yet, little is known about tumor cell-intrinsic PD-1 pathway effects. Here, we show that murine and human melanomas contain PD-1-expressing cancer subpopulations and demonstrate that melanoma cell-intrinsic PD-1 promotes tumorigenesis, even in mice lacking adaptive immunity. PD-1 inhibition on melanoma cells by RNAi, blocking antibodies, or mutagenesis of melanoma-PD-1 signaling motifs suppresses tumor growth in immunocompetent, immunocompromised, and PD-1-deficient tumor graft recipient mice. Conversely, melanoma-specific PD-1 overexpression enhances tumorigenicity, as does engagement of melanoma-PD-1 by its ligand, PD-L1, whereas melanoma-PD-L1 inhibition or knockout of host-PD-L1 attenuate growth of PD-1-positive melanomas. Mechanistically, the melanoma-PD-1 receptor modulates downstream effectors of mTOR signaling. Our results identify melanoma cell-intrinsic functions of the PD-1:PD-L1 axis in tumor growth and suggest that blocking melanoma-PD-1 might contribute to the striking clinical efficacy of anti-PD-1 therapy.

Intravital and whole-organ imaging reveals capture of melanoma-derived antigen by lymph node subcapsular macrophages leading to widespread deposition on follicular dendritic cells.

Aberrant antigens expressed by tumor cells, such as in melanoma, are often associated with humoral immune responses, which may in turn influence tumor progression. Despite recent data showing the central role of adaptive immune responses on cancer spread or control, it remains poorly understood where and how tumor-derived antigen (TDA) induces a humoral immune response in tumor-bearing hosts. Based on our observation of TDA accumulation in B cell areas of lymph nodes (LNs) from melanoma patients, we developed a pre-metastatic B16.F10 melanoma model expressing a fluorescent fusion protein, tandem dimer tomato, as a surrogate TDA. Using intravital two-photon microscopy (2PM) and whole-mount 3D LN imaging of tumor-draining LNs in immunocompetent mice, we report an unexpectedly widespread accumulation of TDA on follicular dendritic cells (FDCs), which were dynamically scanned by circulating B cells. Furthermore, 2PM imaging identified macrophages located in the subcapsular sinus of tumor-draining LNs to capture subcellular TDA-containing particles arriving in afferent lymph. As a consequence, depletion of macrophages or genetic ablation of B cells and FDCs resulted in dramatically reduced TDA capture in tumor-draining LNs. In sum, we identified a major pathway for the induction of humoral responses in a melanoma model, which may be exploitable to manipulate anti-TDA antibody production during cancer immunotherapy.

Nail melanoma in situ: clinical, dermoscopic, pathologic clues, and steps for minimally invasive treatment

BACKGROUND Nail unit melanoma (NUM) is a variant of acral lentiginous melanoma. The differential diagnosis is wide but an acquired brown streak in the nail of a fair-skinned adult person must be considered a potential melanoma. Dermoscopy helps clinicians to more accurately decide if a nail apparatus biopsy is necessary. OBJECTIVE Detailed evaluation of clinical and dermoscopy features and description of conservative surgery of in situ NUM. METHODS Retrospective study of in situ NUM diagnosed and treated with conservative surgical management in the authors' center from 2008 to 2013. RESULTS Six cases of NUM were identified: 2 male and 4 female patients, age range at diagnosis of 44 to 76 years. All patients underwent complete nail unit removal with at least 6-mm security margins around the anatomic boundaries of the nail. The follow-up varies from 4 to 62 months. CONCLUSION Nail unit melanomas pose a difficult diagnostic and therapeutic challenge. Wide excision is sufficient, whereas phalanx amputation is unnecessary and associated with significant morbidity for patients with in situ or early invasive melanoma. Full-thickness skin grafting or second-intention healing after total nail unit excision is a simple procedure providing a good functional and cosmetic outcome.

Sildenafil Potentiates a cGMP-Dependent Pathway to Promote Melanoma Growth.

Sildenafil, an inhibitor of the cGMP-degrading phosphodiesterase 5 that is used to treat erectile dysfunction, has been linked to an increased risk of melanoma. Here, we have examined the potential connection between cGMP-dependent signaling cascades and melanoma growth. Using a combination of biochemical assays and real-time monitoring of melanoma cells, we report a cGMP-dependent growth-promoting pathway in murine and human melanoma cells. We document that C-type natriuretic peptide (CNP), a ligand of the membrane-bound guanylate cyclase B, enhances the activity of cGMP-dependent protein kinase I (cGKI) in melanoma cells by increasing the intracellular levels of cGMP. Activation of this cGMP pathway promotes melanoma cell growth and migration in a p44/42 MAPK-dependent manner. Sildenafil treatment further increases intracellular cGMP concentrations, potentiating activation of this pathway. Collectively, our data identify this cGMP-cGKI pathway as the link between sildenafil usage and increased melanoma risk.