Primary melanoma anatomic location is an independent predictor of SLN status and survival. Although HNM has a decreased SLN-positivity rate, it shows a significantly increased risk of recurrence and death as compared with other sites.
Background:Bromodomain PHD finger transcription factor (BPTF) plays an important role in chromatin remodeling, but its functional role in tumor progression is incompletely understood. Here we explore the oncogenic effects of BPTF in melanoma.Methods:The consequences of differential expression of BPTF were explored using shRNA-mediated knockdown in several melanoma cell lines. Immunoblotting was used to assess the expression of various proteins regulated by BPTF. The functional role of BPTF in melanoma progression was investigated using assays of colony formation, invasion, cell cycle, sensitivity to selective BRAF inhibitors, and in xenograft models of melanoma progression (n = 12 mice per group). The biomarker role of BPTF in melanoma progression was assessed using fluorescence in situ hybridization and immunohistochemical analyses. All statistical tests were two-sided.Results:shRNA-mediated BPTF silencing suppressed the proliferative capacity (by 65.5%) and metastatic potential (by 66.4%) of melanoma cells. Elevated BPTF copy number (mean ≥ 3) was observed in 28 of 77 (36.4%) melanomas. BPTF overexpression predicted poor survival in a cohort of 311 melanoma patients (distant metastasis-free survival P = .03, and disease-specific survival P = .008), and promoted resistance to BRAF inhibitors in melanoma cell lines. Metastatic melanoma tumors progressing on BRAF inhibitors contained low BPTF-expressing, apoptotic tumor cell subclones, indicating the continued presence of drug-responsive subclones within tumors demonstrating overall resistance to anti-BRAF agents.Conclusions:These studies demonstrate multiple protumorigenic functions for BPTF and identify it as a novel target for anticancer therapy. They also suggest the combination of BPTF targeting with BRAF inhibitors as a novel therapeutic strategy for melanomas with mutant BRAF.
Although melanomas with mutant v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) can now be effectively targeted, there is no molecular target for most melanomas expressing wildtype BRAF. Here, we show that the activation of Pleckstrin homology domain-interacting protein (PHIP), promotes melanoma metastasis, can be used to classify a subset of primary melanomas, and is a prognostic biomarker for melanoma. Systemic, plasmidbased shRNA targeting of Phip inhibited the metastatic progression of melanoma, whereas stable suppression of Phip in melanoma cell lines suppressed metastatic potential and prolonged the survival of tumor-bearing mice. The human PHIP gene resides on 6q14.1, and although 6q loss has been observed in melanoma, the PHIP locus was preserved in melanoma cell lines and patient samples, and its overexpression was an independent adverse predictor of survival in melanoma patients. In addition, a high proportion of PHIP-overexpressing melanomas harbored increased PHIP copy number. PHIP-overexpressing melanomas include tumors with wild-type BRAF, neuroblastoma RAS viral (v-ras) oncogene homolog, and phosphatase and tensin homolog, demonstrating PHIP activation in triple-negative melanoma. These results describe previously unreported roles for PHIP in predicting and promoting melanoma metastasis, and in the molecular classification of melanoma.T he successful development of targeted therapy for melanomas harboring BRAF mutations has garnered significant attention, given the promising results of small molecule inhibitors of mutant BRAF (1). However, the molecular basis underlying the metastasis of the ≈50% of all human melanomas that lack a BRAF mutation, and specific targets for the therapy of these melanomas, is unclear. As a result, "triple-negative melanoma" patients, whose tumors harbor wild-type v-Raf murine sarcoma viral oncogene homolog B1 (BRAF), neuroblastoma RAS viral (vras) oncogene homolog (NRAS), and phosphatase and tensin homolog (PTEN) (the most common mutations observed in melanoma), are not candidates for most targeted therapies developed to date.The type I insulin-like growth factor receptor (IGF1R) signaling pathway has been recognized to play an increasingly important role in tumorigenesis (2, 3). Binding of IGF1 or IGF2 to IGF1R results in phosphorylation of tyrosine and carboxyl-terminal serine residues that form binding sites for the insulin-receptor substrate (IRS) docking proteins. IRS activation results in PI3K recruitment and AKT activation (4). Efficient docking of IRS proteins is mediated via their pleckstrin homology domain. Pleckstrin homology domain-interacting protein (PHIP), initially identified through interactions with the pleckstrin homology domain of IRS proteins, has been shown to mediate transcriptional responses in pancreatic islet cells (5), and is important for postnatal growth (6). Previously, we identified PHIP as the gene most highly overexpressed in metastatic melanomas, compared with primary tumors by cDNA microarray analysis (7). Although PHIP plays a r...
SLN biopsy is accurate in head and neck melanoma and provides significant prognostic data. Scalp melanoma patients present with thicker tumors with an increase in SLN positivity and false-negative SLN occurrences.
For primary melanoma, there is a delay between the initial skin biopsy and sentinel lymph node dissection, which may cause anxiety for the patient. The consequences of this delay on disease progression are unknown. The goal of this study was to determine whether delay time for sentinel node dissection from the initial cutaneous melanoma biopsy affects patient outcomes. A retrospective analysis of 492 patients with melanoma who underwent a sentinel node dissection between 1993 and 1999 was carried out. The endpoints assessed were sentinel node tumor status, recurrence, and mortality. Time to sentinel node dissection was compared between patients with positive and negative sentinel nodes. Long-term survival and recurrence were evaluated in relation to the time between the cutaneous biopsy and the sentinel node dissection (delay time), comparing less than 40 days with at least 40 days. In total, 15.9% of patients had positive sentinel nodes. The median follow-up was 11.7 years. Positive sentinel node patients had a median delay of 35 days between the primary melanoma biopsy and the sentinel node dissection compared with 41 days for negative sentinel node patients (P=0.5). Kaplan-Meier survival curves showed that a delay time of less than 40 days versus at least 40 days was not related to recurrence of melanoma (log-rank P=0.13) or overall survival (log-rank P=0.14). On multivariate analysis of age, thickness, ulceration, and sentinel node status, there was no difference in disease-free survival (P=0.58) or overall survival (P=0.53) between the less than 40 days and the at least 40 days groups. A modest delay in sentinel node dissection from the initial melanoma biopsy does not adversely affect sentinel node status, recurrence, nor survival.
To decrease the miss rate, all SLNs with ≥10% of the ex vivo radioactivity of the "hottest" SLN should be removed and blue dye is not essential.
Ulceration is an important prognostic factor in melanoma whose biologic basis is poorly understood. Here we assessed the prognostic impact of pleckstrin homology domain-interacting protein (PHIP) copy number and its relationship to ulceration. PHIP copy number was determined using fluorescence in situ hybridization (FISH) in a tissue microarray cohort of 238 melanomas. Elevated PHIP copy number was associated with significantly reduced DMFS (P = 0.01) and DSS (P = 0.009) by Kaplan-Meier analyses. PHIP FISH scores were independently predictive of DMFS (P = 0.03) and DSS (P = 0.03). Increased PHIP copy number was an independent predictor of ulceration status (P = 0.04). The combined impact of increased PHIP copy number and tumor vascularity on ulceration status was highly significant (P< 0.0001). Stable suppression of PHIP in human melanoma cells resulted in significantly reduced glycolytic activity in vitro, with lower expression of LDH5, HIF1A, and VEGF, and was accompanied by reduced microvessel density in vivo. These results provide further support for PHIP as a molecular prognostic marker of melanoma, and reveal a significant linkage between PHIP levels and ulceration. Moreover, they suggest that ulceration may be driven by increased glycolysis and angiogenesis.
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