A Seven-Marker Signature and Clinical Outcome in Malignant Melanoma: A Large-Scale Tissue-Microarray Study with Two Independent Patient Cohorts

Abstract

BackgroundCurrent staging methods such as tumor thickness, ulceration and invasion of the sentinel node are known to be prognostic parameters in patients with malignant melanoma (MM). However, predictive molecular marker profiles for risk stratification and therapy optimization are not yet available for routine clinical assessment.Methods and FindingsUsing tissue microarrays, we retrospectively analyzed samples from 364 patients with primary MM. We investigated a panel of 70 immunohistochemical (IHC) antibodies for cell cycle, apoptosis, DNA mismatch repair, differentiation, proliferation, cell adhesion, signaling and metabolism. A marker selection procedure based on univariate Cox regression and multiple testing correction was employed to correlate the IHC expression data with the clinical follow-up (overall and recurrence-free survival). The model was thoroughly evaluated with two different cross validation experiments, a permutation test and a multivariate Cox regression analysis. In addition, the predictive power of the identified marker signature was validated on a second independent external test cohort (n = 225). A signature of seven biomarkers (Bax, Bcl-X, PTEN, COX-2, loss of β-Catenin, loss of MTAP, and presence of CD20 positive B-lymphocytes) was found to be an independent negative predictor for overall and recurrence-free survival in patients with MM. The seven-marker signature could also predict a high risk of disease recurrence in patients with localized primary MM stage pT1-2 (tumor thickness ≤2.00 mm). In particular, three of these markers (MTAP, COX-2, Bcl-X) were shown to offer direct therapeutic implications.ConclusionsThe seven-marker signature might serve as a prognostic tool enabling physicians to selectively triage, at the time of diagnosis, the subset of high recurrence risk stage I–II patients for adjuvant therapy. Selective treatment of those patients that are more likely to develop distant metastatic disease could potentially lower the burden of untreatable metastatic melanoma and revolutionize the therapeutic management of MM.

Development of a Prognostic Genetic Signature to Predict the Metastatic Risk Associated with Cutaneous Melanoma

“…The prognostic power of this assay is considerably greater than other reported prognostic assays for melanoma. For example, the Kaplan-Meier analysis of a protein-based prognostic signature from Meyer and colleagues resulted in 5-year MFS rates of about 70% (median, 7.3 years) versus 35% (median, 2.75 years) for low-risk compared with highrisk patients, respectively, whereas Harbst and colleagues reported 5-year MFS rates of approximately 85% (median not reached) and 40% (median, 3.75 years) for low-and high-grade forms of melanoma, respectively (25,35).…”

Regulating the response to targeted MEK inhibition in melanoma

“…Furthermore, high cytoplasmic and/or nuclear β-catenin staining of patient tumor biopsies correlates with increased patient survival, decreased metastasis recurrence and decreased expression of proliferation markers. 19,22,23 Supportingly, high Wnt/β-catenin signaling mediated by overexpression of WNT3A inhibits tumor growth in mouse models of melanoma, accompanied by an increased expression of melanocyte-associated gene targets. 22,24 In light of the inhibitory role for Wnt/β-catenin signaling in this context as well as existing clinical efforts to target BRAF-mediated signaling in melanoma, we examined the combinatorial effects of Wnt/β-catenin activation with ERK/ MAPK inhibition.…”

“…24 These studies also raise the question of whether activation of Wnt/β-catenin may have some therapeutic role in enhancing melanoma patient responses to targeted BRAF inhibition. Three large studies using independent tumor microarrays totaling over 1,000 patient tumors have associated increased levels of nuclear or cytosolic β-catenin in patient melanoma tumors with improved patient survival, 19,22,23 so consideration of Wnt/β-catenin activation as a therapeutic approach has already been broached.…”

Recent progress in protein profiling of clinical tissues for next-generation molecular diagnostics

“…A sevenprotein signature was found that might be used as a prognostic tool to estimate the overall and recurrence-free survival of MM patients [79]. Using TMA containing 60 pairs of primary hepatocellular carcinomas (HCCs) and their matched metastases as well as 30 pairs of primary/recurrent HCCs, Hu et al showed that overexpression of FGF3 was significantly associated with HCC metastasis and recurrence.…”