Do inflammatory pathways drive melanomagenesis?

Inflammatory pathways serve to protect the host and promote tissue healing/repair; however, over-activation or dysregulation can be pathological with unintended consequences including malignant progression. A correlation between inflammation and cancer has been well established, and anti-inflammatory medications have been shown to be chemopreventive in certain malignancies. Data are now becoming available that outline an inflammatory pathway that may have a critical role in melanomagenesis. ATP-regulated membrane channels/receptors P2X7 and PANX1 have been directly implicated in melanoma tumor growth. Among other potential effects, opening of the P2X7/PANX1 channel results in activation of the NALP3 inflammasome, which in turn leads to caspase-1 activation and increased levels of activated IL-1ß. Elevated levels of caspase-1 and IL-1ß have been correlated with melanoma progression, and inhibitors of the inflammasome, caspase and IL-1ß activity have all been shown to inhibit melanoma growth. Among many other potential actions, IL-1ß increases cyclooxygenase-2 expression leading to local increases in inflammatory mediators such as prostaglandin E2 (PGE2). Anti-inflammatory medications targeting the end of this pathway have had positive results for certain cancers but overall remain mixed for melanoma. A better understanding of the pathways and appropriate intervention points may help direct future therapies. In this viewpoint, we will review data and attempt to model an inflammatory pathway that may be critical for melanomagenesis and propose future directions for exploration.

How, and from which cell sources, do nevi really develop?

Melanocytic neoplasms are a diverse group of benign and malignant tumors with variable clinical features. While some models still promote the epidermal melanocyte as the origin of melanocytic neoplasms, clinical findings are inconsistent with this theory for the majority of tumors. Despite advances in naevus and melanoma biology, the location and differentiation status of the cell of origin remains undefined. Germ line genetics, biological state and cellular location of the mutated cell, as well as local environmental factors all likely play a role in the development of melanocytic neoplasms. Herein, we will review potential models for melanocytic neoplasia and discuss research challenges and opportunities.

A simplified minimally invasive technique for the treatment of venous lakes.

A simplified approach to treat venous lakes of the vermillion lip is presented. Our method involves the use of a 30 gauge hypodermic needle to deliver a low-powered, high-frequency electrical current from a hyfrecator power source into the venous lake lesion.

Potential role of human growth hormone in melanoma growth promotion.

BACKGROUND Human growth hormone (HGH) and insulin-like growth factor-1 (IGF-1) have been shown to play a role in the malignant transformation and progression of a variety of cancers. HGH is also known to upregulate molecular signaling pathways implicated in the pathogenesis of melanoma. Although HGH has previously been implicated in promoting the clinical growth of both benign and malignant melanocytic neoplasms, to our knowledge there are no conclusive studies demonstrating an increased risk of melanoma following HGH therapy. Nevertheless, there are reports of melanoma developing subsequent to HGH coadministered with either other hormones or following irradiation. OBSERVATION A 49-year-old white man presented with a new pigmented papule that was diagnosed as melanoma. The patient reported using HGH for 3 months prior to the diagnosis. His 51-year-old wife, who also was white, had also been using exogenous HGH for 3 months and had been diagnosed as having a melanoma 2 weeks prior. CONCLUSIONS Given the unlikelihood of 2 unrelated people developing melanoma within a short time span, it is reasonable to assume that a common environmental component (HGH or other shared exposure) contributed to the development of both melanomas. Because of the increased use of exogenous HGH as an antiaging agent, it is important to be aware of the growth-promoting effects of this hormone. Until better data are available that determines the true risk of exogenous HGH, its use as an antiaging agent merits increased surveillance.

Surgical management of a giant plexiform neurofibroma of the lower extremity.

The authors review their experience with the management of a giant 49-kg (108 lb) neurofibroma of the lower extremity in a 37-year-old male with NF1. The patient presented with right thigh pain, paresthesias, increasing edema, and accelerated growth of the mass. The patient was taken to the operating room, where approximately 39 kg (86 lb) of tumor and 10 L (22 lb) of interstitial fluid was removed. The postoperative course was complicated by cellulitis, delayed wound closure, and recurrent lymphedema. Complications were managed with antibiotics, ultrasound-guided drainage, surgical revision of closure, compressive dressings, passive drainage, and vacuum-assisted wound closure. Giant neurofibromas similar to this tumor require complex intraoperative and postoperative management strategies. Surgical closure is best managed with local flaps, and postoperative lymphedema is best managed with passive drainage and compressive dressings.

Molecular nevogenesis.

Despite recent advances, the biology underlying nevogenesis remains unclear. Activating mutations in NRAS, HRAS, BRAF, and GNAQ have been identified in benign nevi. Their presence roughly correlates with congenital, Spitz, acquired, and blue nevi, respectively. These mutations are likely to play a critical role in driving nevogenesis. While each mutation is able to activate the MAP kinase pathway, they also interact with a host of different proteins in other pathways. The different melanocytic developmental pathways activated by each mutation cause the cells to migrate, proliferate, and differentiate to different extents within the skin. This causes each mutation to give rise to a characteristic growth pattern. The exact location and differentiation state of the cell of origin for benign moles remains to be discovered. Further research is necessary to fully understand nevus development given that most of the same developmental pathways are also present in melanoma.

Nevus senescence.

Melanomas and nevi share many of the same growth-promoting mutations. However, melanomas grow relentlessly while benign nevi eventually undergo growth arrest and stabilize. The difference in their long-term growth potential may be attributed to activation of cellular senescence pathways. The primary mediator of senescence in nevi appears to be p16. Redundant, secondary senescence systems are also present and include the p14-p53-p21 pathway, the IGFBP7 pathway, the FBXO31 pathway, and the PI3K mediated stress induced endoplasmic reticulum unfolded protein response. It is evident that these senescence pathways result in an irreversible arrest in most instances; however, they can clearly be overcome in melanoma. Circumvention of these pathways is most frequently associated with gene deletion or transcriptional repression. Reactivation of senescence mechanisms could serve to inhibit melanoma tumor progression.

Nevogenesis: a benign metastatic process?

It is generally accepted that cutaneous nevogenesis is a localized event that occurs exclusively in the dermis and/or epidermis. However, the discovery of nevocytes circulating in the peripheral blood suggests that other, more systemic, benign metastatic processes could also be involved. The theoretical role of lymphatic and hematogenous dissemination of loosely adherent, immature nevus progenitor cells in the development of nodal nevi and eruptive melanocytic nevi will be reviewed.

Genomic instability in cultured stem cells: associated risks and underlying mechanisms.

Embryonic stem cells, mesenchymal stem cells and induced pluripotent stem cells expanded in vitro exhibit genomic instability. Commonly reported abnormalities include aneuploidy, deletions and duplications (including regions also amplified in cancer). Genomic instability confers an increased risk of malignant transformation that may impact the safety of cultured stem cell transplantation. Possible mechanisms responsible for this genomic instability include DNA repair mechanism abnormalities, telomere crisis, mitotic spindle abnormalities and inappropriate induction of meiotic pathways. Prior to widespread use of these cells in regenerative medicine, it will be critical to gain an understanding of the mechanisms responsible for genomic instability to develop strategies to prevent the accrual of chromosomal defects during expansion in vitro.

The surgical management of symptomatic peripheral nerve sheath tumors.

OBJECTIVE: To determine the clinical presentation and morbidity of the surgical management of peripheral nerve sheath tumors (PNSTs). METHODS: We performed a retrospective chart review of surgically treated PNSTs at the University of Miami between 1991 and 2008. RESULTS: There were a total of 140 cases, including 87 schwannomas, 34 neurofibromas, and 19 malignant peripheral nerve sheath tumors (MPNSTs). The average age of the total study group was 49.0 years; it was significantly lower for patients with neurofibroma. There was a high correlation between neurofibroma tumors and neurofibromatosis-1. Most patients with benign tumors presented with a painful mass, paresthesias, or numbness without significant weakness. Patients who had previously undergone attempted resections and preoperative biopsy had a significantly increased risk (41%) for developing postoperative neurologic deficits when compared with patients who presented with de novo tumors (15%). Intraoperative monitoring appeared to reduce the risk of postoperative motor deficit, particularly in neurofibromas. Most MPNSTs (>80%) were diagnosed at stage IIB or higher and had a combined mortality rate of 31.6% at 78 months. Tumor size was the best predictor of adverse outcome, as all MPNST mortalities occurred in patients with a tumor size of more than 7 cm. CONCLUSION: PNSTs are a heterogeneous group of lesions. Benign tumors respond well to marginal excision, whereas MPNSTs are aggressive sarcomas that require multimodal management. There was a significantly increased risk of postoperative neurologic deficits in patients who had undergone a previous biopsy, and thus tertiary referral without biopsy is recommended when a PNST is suspected.