Molecular Staging in Stage II and III Melanoma Patients and Its Effect on Long-Term Survival

Liquid biopsy for monitoring of tumor dormancy and early detection of disease recurrence in solid tumors

Cancer is one of the three leading causes of death worldwide. Even after successful therapy and achieving remission, the risk of relapse often remains. In this context, dormant residual cancer cells in secondary organs such as the bone marrow constitute the cellular reservoir from which late tumor recurrences arise. This dilemma leads the term of minimal residual disease, which reflects the presence of tumor cells disseminated from the primary lesion to distant organs in patients who lack any clinical or radiological signs of metastasis or residual tumor cells left behind after therapy that eventually lead to local recurrence. Disseminated tumor cells have the ability to survive in a dormant state following treatment and linger unrecognized for more than a decade before emerging as recurrent disease. They are able to breakup their dormant state and to readopt their proliferation under certain circumstances, which can finally lead to distant relapse and cancer-associated death. In recent years, extensive molecular and genetic characterization of disseminated tumor cells and blood-based biomarker has contributed significantly to our understanding of the frequency and prevalence of tumor dormancy. In this article, we describe the clinical relevance of disseminated tumor cells and highlight how latest advances in different liquid biopsy approaches can be used to detect, characterize, and monitor minimal residual disease in breast cancer, prostate cancer, and melanoma patients.

Current Trends in Circulating Biomarkers for Melanoma Detection

Melanomas have increased in global incidence and are the leading cause of skin cancer deaths. Whilst the majority of early-stage, non-metastatic melanomas can be cured with surgical excision alone, ~5% of patients with early melanomas will experience recurrence following a variable disease-free interval and progression to metastatic melanoma and ultimately death. This is likely because of primary tumor heterogeneity and progressive clonal divergency resulting in the growth of more aggressive tumor populations. Liquid biomarkers have the advantage of real-time, non-invasive longitudinal monitoring of tumor burden and heterogeneity over tissue markers. Currently, the only serological marker used in the staging and monitoring of melanoma is serum lactate dehydrogenase, which is not sufficiently specific or sensitive, and is not used routinely in all centers. An ideal melanoma biomarker would be used to identify patients who are at high-risk of primary melanoma, screen for relapse, detect early-stage melanoma, provide treatment outcomes to personalize systemic treatment, follow tumor heterogeneity, provide prognostic data before, during and after treatment, and monitor response to treatment. This review provides a summary of the current research in this field with a specific focus on circulating tumor cells, circulating tumor DNA, microRNA, and extracellular vesicles which may serve to suit these goals.

Circulating biomarkers in malignant melanoma

Melanoma is an aggressive tumor with increasing incidence worldwide. Biomarkers are valuable tools to minimize the cost and improve efficacy of treatment of this deadly disease. Serological markers have not widely been introduced in routine clinical practice due to their insufficient diagnostic sensitivity and specificity. It is likely that the lack of objective responses with traditional treatment hinder biomarker research and development in melanoma. Recently, new drugs and therapies have, however, emerged in advanced melanoma with noticeable objective response ratio and survival. In this new scenario, serological tumor markers should be revisited. In addition, other potential circulating biomarkers such as cell-free DNA, exosomes, microRNA, and circulating tumor cells have also been identified. In this review, we summarize classical and emerging tumor markers and discuss their possible roles in emerging therapeutics.

Circulating tumour cells as tumour biomarkers in melanoma: detection methods and clinical relevance

Circulating tumour cells (CTCs) are cells of solid tumour origin detectable in the peripheral blood. Their occurrence is considered a prerequisite step for establishing distant metastases. Metastatic melanoma was the first malignancy in which CTCs were detected and numerous studies have been published on CTC detection in melanoma at various stages of disease. In spite of this, there is no general consensus as to the clinical utility of CTCs in melanoma, largely due to conflicting results from heterogeneous studies and discrepancies in methods of detection between studies. In this review, we examine the possible clinical significance of CTCs in cutaneous, mucosal and ocular melanoma, focusing on detection methods and prognostic value of CTC detection.

Circulating serologic and molecular biomarkers in malignant melanoma

The worldwide incidence of malignant melanoma has been increasing during the past decade and is a public health concern because this disease accounts for up to 90% of deaths from cutaneous malignancies. It remains a devastating disease with few therapeutic options once in an advanced stage. Current methods of detection, prognostication, and monitoring of melanoma focus on clinical, morphologic, and histopathologic characteristics of measurable tumor. Although this information provides some insight into disease behavior and outcome, melanoma is still an unpredictable disease. Significant effort has been put into finding an informative serologic biomarker. However, the marker remains elusive, and investigations continue. Using the PubMed database, we reviewed the published literature on serologic melanoma biomarkers and present a synopsis of the extensive investigations that have been performed thus far, provide some insight into why most have failed to become incorporated into routine clinical use, and present an overview of innovative methods currently being explored.

Prognostic molecular biomarkers for cutaneous malignant melanoma

Molecular signatures of melanoma have propelled new approaches to early diagnosis, monitoring of treatment response, and targeted therapy. This review discusses messenger RNA (mRNA), genomic, and epigenomic melanoma biomarkers in blood and tissue specimens. The major focus is on tissue-based molecular assays to upstage sentinel lymph nodes (SLNs), and blood-based assays to detect melanoma progression by monitoring levels of circulating tumor cells (CTC) and circulating DNA.

Methods of detection of circulating melanoma cells: a comparative overview

Disease dissemination is the major cause of melanoma-related death. A crucial step in the metastatic process is the intravascular invasion and circulation of melanoma cells in the bloodstream with subsequent development of distant micrometastases that is initially clinically undetectable and will eventually progress into clinically apparent metastasis. Therefore, the use of molecular methods to detect circulating melanoma cells may be of value in risk stratification and clinical management of such patients. Herein, we review the currently applied techniques for the detection, isolation, enrichment and further characterization of circulating melanoma cells from peripheral blood samples in melanoma patients. Furthermore, we provide a brief overview of the various molecular markers currently being evaluated as prognostic indicators of melanoma progression.

Quantitative detection of melanoma-associated antigens by multimarker real-time RT-PCR for molecular staging: results of a 5 years study

INTRODUCTION

Monitoring of circulating melanoma cells in the peripheral blood is a promising method for identifying a subgroup of patients with minimal residual disease.

OBJECTIVES

To evaluate the prognostic impact of melanoma-associated antigens by multimarker real-time RT-PCR for disease-specific survival time.

METHODS

Five melanoma markers: Melan-A, gp 100, MAGE-3, MIA and tyrosinase were detected by a quantitative multimarker real-time reverse transcription-PCR (RT-PCR). We included 65 patients with resected melanoma in stage II-III. Peripheral blood samples were examined every 3 months for 2 years. The expression of melanoma markers in 2925 RT-PCR assays was correlated with clinical staging results in total of 5 years.

RESULTS

Twenty-seven patients relapsed during the study period and 26 of them revealed positive markers. MAGE-3 was the most sensitive progression marker in single occurrence or in combination with MIA and gp 100. The time distribution of metastases during the screened period was as follows: progression in the first year was observed in 40.7% patients, second year in 25.9%, third year in 18.6%, fourth and fifth year in 7.4% equally.

CONCLUSIONS

Statistically significant tumor marker elevation during the first 2 years after the surgical treatment correlates with a worse prognosis of patients. In contrast, the group showing negative real-time RT-PCR results in 24 months serial blood testing was associated with prolonged 5-year disease-specific survival. Therefore, quantitative detection of melanoma-specific molecular markers in the presented setting represents a useful tool for selecting patients in a higher risk of disease recurrence.

Multimarker reverse transcriptase-polymerase chain reaction assay in lymphatic drainage and sentinel node tumor burden

PURPOSE

We assessed molecular (presence of melanoma cells markers in lymph fluid [LY]) and pathological features (sentinel lymph node [SN] tumor burden according to Rotterdam criteria, metastases microanatomic location) and correlated them with survival and melanoma prognostic factors in a group of patients with positive SN biopsy.

METHODS

We analyzed 368 consecutive SN-positive patients after completion lymph node dissection (CLND). In 321 patients we obtained data on SLN microanatomic location/tumor burden (only 7 cases had metastases <0.1 mm); in 137 we additionally analyzed 24-hour collected LY after CLND (multimarker reverse transcriptase-polymerase chain reaction [MM-RT-PCR] with primers for tyrosinase, MART1 (MelanA), and uMAGE mRNA (27.7% positive samples)]. Median follow-up time was 41 months.

RESULTS

According to univariate analysis, the following factors had a negative impact on overall survival (OS): higher Breslow thickness (P = .0001), ulceration (P < .0001), higher Clark level (P = .008), male gender (P = .0001), metastatic lymph nodes >1 (P < .0001), nodal metastases extracapsular extension (P < .0001), metastases to additional non-SNs (P = .0004), micrometastases size ≥ 0.1 mm (P = .0006), and positive LY MM-RT-PCR (P = .0007). SN tumor burden showed linear correlation with increasing Breslow thickness (P = .01). The 5-year OS rates for SLN tumor burden <0.1 mm, 1-1.0 mm, and >1.0 mm were 84%/66%/44%, respectively, and for positive and negative LY MM-RT-PCR 47%/0%, respectively. The independent factors for shorter OS (multivariate analysis): male gender, primary tumor ulceration, number of involved nodes ≥ 4, micrometastases size >1.0 mm, and, in additional model including molecular analysis-positive MM-RT-PCR results (hazard ratio [HR] 3.2), micrometastases size >1.0 mm (HR 1.13), and primary tumor ulceration (HR 2.17). Similar results were demonstrated for disease-free survival (DFS) data.

CONCLUSIONS

SN tumor burden categories according to Rotterdam criteria and the positive result of LY MM-RT-PCR assay demonstrated additional, independent prognostic value in SN-positive melanoma patients, showing significant correlation with shorter DFS and OS.

Serial monitoring of circulating tumor cells predicts outcome of induction biochemotherapy plus maintenance biotherapy for metastatic melanoma

PURPOSE

Molecular biomarkers in blood are promising for assessment of tumor progression and treatment response. We hypothesized that serial monitoring of circulating tumor cells (CTC) with the use of multimarker quantitative real-time reverse transcriptase-PCR assays could be a surrogate predictor of outcome for melanoma patients enrolled in a multicenter phase II clinical trial of biochemotherapy (BCT) combined with maintenance biotherapy (mBT).

EXPERIMENTAL DESIGN

Blood specimens were collected from 87 patients before and during induction BCT and mBT for stage IV melanoma. Expression of five melanoma-associated CTC biomarkers (MART-1, GalNAc-T, PAX-3, MAGE-A3, and Mitf) was assessed by quantitative real-time reverse transcriptase-PCR, and correlated with treatment response and disease outcome.

RESULTS

The number of positive CTC biomarkers decreased overall during induction BCT (P < 0.0001). CTC biomarker detection after two cycles of BCT was correlated with treatment response (P = 0.005) and overall survival (P = 0.001): an increase in the number of CTC biomarkers was associated with poor response (P = 0.006) and overall survival (P < 0.0001). Multivariate analyses with the use of a Cox proportional hazards model identified the change in CTC biomarkers after two cycles of BCT as an independent prognostic factor for disease progression (risk ratio, 12.6; 95% confidence interval, 4.78-33.4; P < 0.0001) and overall survival (risk ratio, 6.11; 95% confidence interval, 2.37-15.7; P = 0.0005).

CONCLUSION

Serial monitoring of CTC during induction BCT may be useful for predicting therapeutic efficacy and disease outcome in patients receiving BCT and mBT for stage IV melanoma.

A new standardized absolute quantitative RT-PCR method for detection of tyrosinase mRNAs in melanoma patients: technical and operative instructions

BACKGROUND

To develop a new absolute quantitative real-time PCR method for blood mRNA tyrosinase assay and to compare this new method with standard RT-PCR nested.

METHODS

Ten blood of melanoma patients (stages I-III), 5 tissue samples, 2 surgical fresh metastatic skin and 3 lymph nodes paraffin-embedded slices were analysed, and 10 negative controls were used. Ten millilitres of blood was analysed for each individual. Three different protocols for RNA extraction and two reverse transcription methods were used. Specific human tyrosinase cDNA fragment was cloned into pcDNA3+ vector and then titrated for the standard curve construction (from 10(6) to 10(1)copies/microl). Recovery assays for RNA and cells were also performed.

RESULTS

Our method was able to detect less than 5 cells/10(8) WBC and about 100 fg of tyrosinase RNA. Very low CVs (<1.5%) were obtained on all samples run in triplicate. Sensitivity and specificity were of 100%. The amount of starting volume of blood was crucial for the determination of copy number since large volumes are necessary for patient's monitoring.

CONCLUSIONS

Our absolute qRT-PCR assay could be proposed as a new standardized molecular method for the management of melanoma patients, particularly for the follow up of the highest AJCC stages.

Molecular staging by multimarker reverse transcriptase-polymerase chain reaction assay of lymphatic drainage and blood from melanoma patients after lymph node dissection

Reverse transcriptase-polymerase chain reaction (RT-PCR)-mediated detection of melanoma cells may be a prognostic factor for disease outcome. We investigated the presence of melanoma cells in lymphatic drainage and blood in melanoma patients after lymph node dissection (LND) via the highly sensitive multimarker (MM) RT-PCR assay. We collected 24-h lymph fluid (LY) and peripheral blood (BL) from 107 stage III melanoma patients after radical LND (59 axillary and 48 ilioinguinal LND). Tyrosinase, MART1 and uMAGE mRNA levels were determined by RT-PCR to detect melanoma cells, and the presence of at least one marker signified a positive result. All patients underwent follow-up (median for survivors, 21 months, range: 4-37 months). Forty patients (37.4%) were positive for LY MM RT-PCR and 28 (26.2%) were positive based on BL MM RT-PCR. No differences for disease-free survival (DFS) curves according to BL MM RT-PCR were observed, but we found significant differences in the estimated 24-month DFS rate for patients with at least one marker and those without any marker in lymph fluid [18.9% (95% confidence interval: 1.4-37.5%) and 42.1% (95% confidence interval: 29.7-54.5%), median: 9.9 and 15.3 months, respectively] (P=0.04). Detection of multiple markers in lymph fluid correlated with shorter DFS. Approximately 37% of lymph fluid after radical LND were positive by MM RT-PCR, which correlated significantly with early melanoma recurrences and shorter survival. The LY MM RT-PCR seems to be an effective prognostic tool for stage III melanoma patients. The MM RT-PCR analysis of single peripheral blood sample in these patients did not have additional prognostic value.

Impact of Molecular Staging Methods in Primary Melanoma: Reverse-Transcriptase Polymerase Chain Reaction (RT-PCR) of Ultrasound-Guided Aspirate of the Sentinel Node Does Not Improve Diagnostic Accuracy, But RT-PCR of Peripheral Blood Does Predict Survival

Purpose

This study analyzes (1) the value of tyrosinase reverse-transcriptase polymerase chain reaction (RT-PCR) of aspirates obtained by ultrasound-guided fine-needle aspiration cytology (US-FNAC) of sentinel nodes (SNs) in patients with melanoma before sentinel lymph node biopsy (SLNB) and (2) the value of RT-PCR of blood samples of all SLNB patients.

Patients and Methods

Between 2001 and 2003, 127 patients with melanoma (median Breslow depth, 2.1 mm) underwent SLNB. FNAC was performed in all SNs of all patients pre- and post-SLNB. The aspirates were partly shock-frozen for RT-PCR and were partly used for standard cytology. Peripheral blood was collected at the time of SLNB and at every outpatient visit thereafter.

Results

Thirty-four (23%) of 120 SNs were positive for melanoma. SN involvement was predicted by US-FNAC with a sensitivity of 82% and a specificity of 72%. Additional tyrosinase RT-PCR revealed the same sensitivity of 82% and a specificity of 72%. At a median follow-up time of 40 months from first blood sample, peripheral-blood RT-PCR was a significant independent predictor of disease-free survival (DFS) and overall survival (OS; P < .001).

Conclusion

US-FNAC is highly accurate and eliminates the need for SLNB in 16% of all SLNB patients. RT-PCR of the aspirate or excised SN does not improve sensitivity or specificity. RT-PCR of blood samples predicts DFS and OS.

Molecular and biochemical testing in stage III melanoma: multimarker reverse transcriptase-polymerase chain reaction assay of lymph fluid after lymph node dissection and preoperative serum lactate dehydrogenase level

BACKGROUND

There is a need for biomarkers to identify patients at risk for disease progression after resection of melanoma regional lymph node metastasis.

OBJECTIVES

This study assessed the prognostic value of multimarker reverse transcriptase-polymerase chain reaction (RT-PCR) assay in lymphatic drainage (LY) after lymph node dissection (LND) and of preoperative serum lactate dehydrogenase (LDH) levels in American Joint Committee on Cancer (AJCC) stage III melanoma patients.

METHODS

We collected 24-h LY from 255 stage III melanoma patients after radical LND [114, completion LND after positive sentinel node biopsy (CLND); 141, therapeutic LND for clinically/cytologically detected regional nodal metastases (TLND)]. For detection of melanoma cells, RT-PCR assays with primers specific for tyrosinase, MART1 (MelanA) and uMAGE mRNA were conducted. The LY sample was deemed positive if at least one marker was detected. In 244 patients, the preoperative serum LDH level was available. Median follow-up time was 25 months (range 5-60).

RESULTS

The LY multimarker RT-PCR assay results were positive in 82 of 255 patients (32%). A significantly higher rate of melanoma recurrence was observed in patients with positive LY multimarker RT-PCR results (P = 0.01). Significant relationships were observed between positive LY multimarker RT-PCR results and shorter 3-year overall survival (OS) and disease-free survival (DFS), both in univariate and multivariate analyses (P = 0.007). Preoperative serum LDH level was increased in 79 of 244 patients (32%) [40.5% in TLND group and 23.0% in CLND group (P = 0.003)]. There were significant differences in OS between patients with normal and high preoperative LDH levels (P = 0.007), and these differences were seen mainly in patients in the TLND group.

CONCLUSIONS

The multimarker RT-PCR assay detected melanoma cells in approximately 32% of LY after LND, which correlated significantly with early melanoma recurrence and shorter survival. Increased pre-LND serum LDH level had an additional negative impact on OS of melanoma patients with palpable nodal metastases after TLND.

Circulating tumor cells: detection, molecular profiling and future prospects

Disseminated malignancy is responsible for the vast majority of cancer-related deaths. During this process, circulating tumor cells (CTC) are generated, spread from the primary tumor, colonize distant organs and lead to overt metastatic disease. CTC are essential for establishing metastasis; however, they are not sufficient as this process is highly inefficient and most will fail to grow in target sites. Several CTC die during migration while others remain dormant for several years and very few grow into macrometastases. CTC have been well documented in the bloodstream of cancer patients; however, the clinical relevance of this detection is still the subject of controversies and their biology is poorly understood. Indeed, available markers fail to distinguish between subgroups of CTC, and several current methods lack sensitivity, specificity or reproducibility in CTC characterization and detection. The advent of more precise technologies is renewing the interest in CTC biology. We will review herein recent findings on CTC biology, on the role of host-tumor interactions in CTC shedding and implantation, available methods of CTC detection and future perspectives for the molecular characterization of the CTC subset(s) responsible for the development of metastasis. Ultimately, understanding CTC biology and host-tumor 'complementarities' will help define metastasis-related biomarkers providing formidable and tailored novel therapeutic targets.

Issues affecting molecular staging in the management of patients with melanoma

Prediction of metastatic potential remains one of the main goals to be pursued in order to better assess the risk subgroups of patients with melanoma. Detection of occult melanoma cells in peripheral blood (circulating metastatic cells [CMC]) or in sentinel lymph nodes (sentinel node metastatic cells [SNMC]), could significantly contribute to better predict survival in melanoma patients. An overview of the numerous published studies indicate the existence of several drawbacks about either the reliability of the approaches for identification of occult melanoma cells or the clinical value of CMC and SNMC as prognostic factors among melanoma patients. In this sense, characterization of the molecular mechanisms involved in development and progression of melanoma (referred to as melanomagenesis) could contribute to better classify the different subsets of melanoma patients. Increasing evidence suggest that melanoma develops as a result of accumulated abnormalities in genetic pathways within the melanocytic lineage. The different molecular mechanisms may have separate roles or cooperate during all evolutionary phases of melanocytic tumourigenesis, generating different subsets of melanoma patients with distinct aggressiveness, clinical behaviour, and response to therapy. All these features associated with either the dissemination of occult metastatic cells or the melanomagenesis might be useful to adequately manage the melanoma patients with different prognosis as well as to better address the different melanoma subsets toward more appropriate therapeutic approaches.

Circulating tumor cells as prognostic factor for distant metastases and survival in patients with primary uveal melanoma

PURPOSE

The aim of this study was to determine in patients with high-risk primary uveal melanoma whether the detection of circulating tumor cells by quantitative reverse transcription-PCR (RT-PCR) is of prognostic relevance.

EXPERIMENTAL DESIGN

Blood samples from 110 patients with high-risk nonmetastatic uveal melanoma were collected on the occasion of primary treatment or follow-up visit. mRNA expression of tyrosinase and MelanA/MART1 were analyzed by real-time RT-PCR and compared with clinical data at presentation and follow-up by univariate and multivariate analyses.

RESULTS

The RT-PCR assay yielded a positive result in 11 of 110 patients, with five positive findings for tyrosinase and five for MelanA/MART1, and one sample positive for both markers. At a median follow-up of 22 months, 25% of patients had developed metastases and 15% had died. Univariate statistical analysis revealed RT-PCR and the largest tumor diameter as important prognostic factors for the development of metastases and for survival. In a Cox proportional hazard model, RT-PCR result and largest tumor diameter predicted metastases (hazard ratios 7.3 and 2.6, respectively), whereas PCR result, largest tumor diameter, and Karnofsky performance status were significant variables for disease-specific survival (hazard ratios 22.6, 4.7, and 6.0, respectively). Analysis of individual RT-PCR results revealed both tyrosinase and MelanA/MART1 transcripts as independent prognostic factors.

CONCLUSION

The presence of tyrosinase or MelanA/MART1 transcripts is an independent prognostic factor in patients with high-risk primary uveal melanoma for subsequent development of metastases and for survival and can be used to select patients for adjuvant treatment studies.

Molecular markers of circulating melanoma cells

Of all skin cancers, cutaneous malignant melanoma (CMM) is the most aggressive and the life expectancy of patients with lymphatic or systemic metastases is dramatically reduced. Understandably therefore, scientists and clinicians have focused on improving diagnostic and prognostic techniques. Of these, perhaps the most promising are multimarker real-time RT-PCR and microarray for detection of circulating CMM cells in peripheral blood. While the optimal set of markers is still to be identified that can accurately assess disease severity and progression at all clinical stages of the disease, recent progress has been dramatic. Here we provide an exhaustive review of recent studies in which a variety of markers are assessed. Moreover, the efficacy of the markers relative to clinical stage is discussed in light of experimental findings. From these studies, it is apparent that researchers are now much closer to defining a set of markers of circulating cells that can be utilized in routine diagnostic tests.

Novel treatment strategies for malignant melanoma: a new beginning?

Malignant melanoma is one of the most common cancer types among the Caucasian population. While the prognosis is excellent for patients diagnosed at an early stage and treated by adequate surgery, unresectable or advanced metastatic diseases shrink the overall survival at 5 years dramatically to less than 10%. For disseminated malignant melanoma, the appropriate systemic medical treatment is still controversial. Fortunately, progress in the molecular biology and in the understanding of pathogenesis has been made recently and should in the near future translate into molecular-based therapeutic strategies. In this review, we briefly describe the status of current treatment strategies and existing standards for malignant melanoma. We will focus on the new and emerging compounds including recent developments of targeted therapy such as antiangiogenic and immunomodulatory drugs, Bcl-2 antisense therapy, raf kinase inhibitors, heat shock protein modulators, anti-cytotoxic T lymphocyte-associated antigen (CTLA)-4 monoclonal antibody and finally PARP and proteasome inhibitors.

Clinical significance of the RT-PCR positive sentinel node in melanoma

BACKGROUND

The clinical relevance of RT-PCR positivity for melanoma markers in the sentinel node remains controversial. Our purpose was to determine whether patients with a histologically negative but RT-PCR positive node were at an increased risk for recurrence than their RT-PCR negative counterparts.

METHODS

Thirty-nine adult patients underwent sentinel node biopsies for melanoma between 1998 and 2000. Each sentinel node was bivalved. Half was serially sectioned and examined by routine hematoxylin and eosin (H&E) and immunohistochemistry (IHC; S100, HMB-45, melanA, and tyrosinase). The other half was analyzed by a nested RT-PCR assay for tyrosinase.

RESULTS

Patients were followed for recurrence with a mean follow-up of 71.1 months. The odds ratio of recurrence for RT-PCR positive versus RT-PCR negative patients was 1.39 (0.34, 5.62; p = 0.73). Within the histology negative subgroups, the risk of recurrence in the RT-PCR positive group (26.7%) was not significantly different from the risk of recurrence in the RT-PCR negative group (22.2%) (p = 0.33 chi-squared). RT-PCR of the sentinel node was not a predictor for recurrence on multivariate analysis (p = 0.65).

CONCLUSION

Sentinel node RT-PCR positivity did not risk stratify histologically negative melanoma patients beyond routine pathologic examination in this series.

Evaluation of prime/boost regimens using recombinant poxvirus/tyrosinase vaccines for the treatment of patients with metastatic melanoma

PURPOSE

Two clinical trials were conducted to evaluate the clinical efficacy and immunologic impact of vaccination against the tyrosinase protein plus systemic interleukin 2 (IL-2) administration in patients with advanced metastatic melanoma.

EXPERIMENTAL DESIGN

Full-length tyrosinase was employed as an immunogen to induce diverse immunologic responses against a commonly expressed melanoma antigen. Heterologous prime/boost vaccination with recombinant vaccinia and fowlpox vectors encoding tyrosinase was first explored in a randomized three-arm phase II trial, in which vaccines were administered alone or concurrently with low-dose or high-dose IL-2. In a subsequent single cohort phase II trial, all patients received the same vaccines and high-dose IL-2 sequentially rather than concurrently.

RESULTS

Among a total of 64 patients treated on these trials, 8 objective partial responses (12.5%) were observed, all in patients receiving high-dose IL-2. Additional patients showed evidence of lesional regression (mixed tumor response) or overall regression that did not achieve partial response status (minor response). In vitro evidence of enhanced immunity against tyrosinase following protocol treatments was documented in 3 of 49 (6%) patients tested serologically, 3 of 23 (13%) patients tested for T-cell recognition of individual tyrosinase peptides, and 4 of 16 (25%) patients tested for T-cell recognition of full-length tyrosinase protein with real-time reverse transcription-PCR techniques.

CONCLUSIONS

Whereas prime/boost immunization with recombinant vaccinia and fowlpox viruses enhanced antityrosinase immunity in some patients with metastatic melanoma, it was ineffective alone in mediating clinical benefit, and in combination with IL-2 did not mediate clinical benefit significantly different from that expected from treatment with IL-2 alone.

Association of circulating tumor cells with serum tumor-related methylated DNA in peripheral blood of melanoma patients

Although previous studies have separately shown the utility of circulating tumor cells (CTC) or cell-free tumor-related DNA in blood of cancer patients, there has been no investigation of their association and/or the prognostic value of combining these assessments. To date, the true source of tumor-related DNA in serum remains unknown. We hypothesized that CTC is a possible origin of serum tumor-related methylated DNA and their combination can predict disease outcome. To test this hypothesis, we obtained matched pairs of peripheral blood lymphocytes and serum specimens simultaneously from 50 American Joint Committee on Cancer stage IV melanoma patients before administration of biochemotherapy. Peripheral blood leukocytes were analyzed for three mRNA markers of CTC: MART-1, GalNAc-T, and MAGE-A3. Sera were analyzed for two methylated DNA markers: RASSF1A and RAR-beta2. CTC were detected in 13 of 15 (86%) patients with serum tumor-related methylated DNA and only in 13 of 35 (37%) patients without methylated DNA (P = 0.001). The number of CTC markers detected significantly correlated with methylated DNA (P = 0.008). CTC and methylated DNA were significantly correlated with biochemotherapy-treated patients' outcome. Patients with both CTC and methylated DNA showed significantly poorer response to biochemotherapy (P = 0.02) and worse time to progression and overall survival (P = 0.009 and 0.02, respectively). The correlation between CTC and serum tumor-related methylated DNA and the significant effect of this correlation on disease outcome indicate that a composite molecular assessment in blood may be a useful determinant of disease status and efficacy of systemic therapy for melanoma.

The prognostic value of circulating tumor cells in patients with melanoma: a systematic review and meta-analysis

BACKGROUND

The detection of circulating tumor cells (CTC) in patients with melanoma represents an appealing prognostic tool, but no consensus exists on this topic. We aimed to comprehensively and quantitatively summarize the evidence for the use of CTC to predict patients' clinical outcome.

METHODS

Fifty-three studies enrolling 5,433 patients were reviewed. Correlation of CTC status with tumor-node-metastasis disease stage and patients' overall (OS) and progression-free (PFS) survival was assessed by means of association statistics and meta-analysis, respectively.

RESULTS

CTC status correlated with both tumor-node-metastasis stage (stage I, 32%; stage II, 41.7%; stage III, 41.1%; stage IV, 47.4%; P(trend) < 0.0001) and survival (OS: hazard ratio, 2.42; 95% confidence interval, 1.7-3.45, P < 0.0001; PFS: hazard ratio, 2.45; 95% confidence interval, 1.78-3.38; P < 0.0001). However, statistical heterogeneity was significant for both OS and PFS, likely underscoring the wide variability in study design. Furthermore, CTC positivity rates in early stages were higher and in the metastatic setting were lower than expected, which indicates an unsatisfactory accuracy of currently available CTC detection assays.

CONCLUSIONS

Our findings suggest that CTC might have a clinically valuable prognostic power in patients with melanoma. However, the heterogeneity of the studies thus far published warrants caution not to overestimate the favorable results of pooled data.

Prospective Multi-Institutional Study of Reverse Transcriptase Polymerase Chain Reaction for Molecular Staging of Melanoma

Purpose

To evaluate the prognostic significance of molecular staging using reverse transcriptase polymerase chain reaction (RT-PCR) in detecting occult melanoma cells in sentinel lymph nodes (SLNs) and circulating bloodstream.

Patients and Methods

In this multicenter study, eligibility criteria included patient age 18 to 71 years, invasive melanoma ≥ 1.0 mm Breslow thickness, and no clinical evidence of metastasis. SLN biopsy and wide excision of the primary tumor were performed. SLNs were examined by serial-section histopathology and S-100 immunohistochemistry. A portion of each SLN was frozen for RT-PCR. In addition, RT-PCR was performed on peripheral-blood mononuclear cells (PBMCs). RT-PCR analysis was performed using four markers: tyrosinase, MART1, MAGE3, and GP-100. Disease-free survival (DFS), distant–DFS (DDFS), and overall survival (OS) were analyzed.

Results

A total of 1,446 patients with histologically negative SLNs underwent RT-PCR analysis. At a median follow-up of 30 months, there was no difference in DFS, DDFS, or OS between the RT-PCR–positive (n = 620) and RT-PCR–negative (n = 826) patients. Analysis of PBMC from 820 patients revealed significant differences in DFS and DDFS, but not OS, for patients with detection of more than one RT-PCR marker in peripheral blood.

Conclusion

In this large, prospective, multi-institutional study, RT-PCR analysis on SLNs and PBMCs provides no additional prognostic information beyond standard histopathologic analysis of SLNs. Detection of more than one marker in PBMC is associated with a worse prognosis. RT-PCR remains investigational and should not be used to direct adjuvant therapy at this time.

Microphthalmia transcription factor as a molecular marker for circulating tumor cell detection in blood of melanoma patients

PURPOSE

Microphthalmia transcription factor (Mitf), which is important in melanocyte development and melanoma growth, was assessed using real-time quantitative reverse transcription-PCR assay to investigate its expression as a marker for circulating melanoma cells in blood and determine the correlation with disease stage and survival in melanoma patients.

EXPERIMENTAL DESIGN

In optimization studies for Mitf, we tested 15 melanoma cell lines, 41 peripheral blood lymphocytes from healthy volunteers, and 21 metastatic melanoma tissues. Blood specimens were procured from 90 patients with stage I (n = 20), stage II (n = 20), stage III (n = 28), and stage IV (n = 22) melanoma. Blood specimens were also obtained at four bleed intervals from 58 patients enrolled in a prospective multicenter trial of biochemotherapy before and after surgical treatment of American Joint Committee on Cancer stage III melanoma.

RESULTS

Under the optimized conditions, Mitf was negative in healthy peripheral blood lymphocytes and positive in all melanoma cell lines and 18 (86%) melanoma tissues. In the 90 patients, the rate of Mitf detection was higher with increasing American Joint Committee on Cancer stage (P < 0.0001). In the 58 patients treated with biochemotherapy and surgery, Mitf detection decreased with treatment (P = 0.019). Mitf detection after treatment was associated with a significantly lower relapse-free (P < 0.0001) and overall (P = 0.001) survival and was a significant independent prognostic factor for relapse-free (risk ratio, 5.63; P = 0.0004) and overall (risk ratio, 5.36; P = 0.005) survival.

CONCLUSIONS

Mitf detection in blood can indicate subclinical metastatic disease and predict treatment outcome in melanoma patients.

Early-Stage Melanoma: Staging Criteria and Prognostic Modeling

Accurate risk assessment is central to the process of making rational surgical and systemic treatment recommendations for melanoma patients and in establishing appropriate clinical trial stratification criteria. The current American Joint Commission on Cancer melanoma staging system incorporated relevant prognostic variables to provide a framework for the estimation of risk for recurrence; however, significant prognostic heterogeneity exists within the stage groupings. In the stage I/II group, survival rates range from 40% to 95% as defined by the combination of tumor thickness and ulceration. The use of novel prognostic factors, such as mitotic rate, sentinel node biopsy, and prognostic modeling using a variety of factors, can minimize this prognostic heterogeneity and provide a more accurate and individualized prognostic profile. Recent modifications in the stage III criteria include the number of positive nodes, whether the nodal disease is microscopic or clinically apparent, and the presence of an ulcerated primary. Through these factors, survival estimates can be provided, but like the stage I/II group, wide ranges in prognosis exist. The complexion of the stage III population is in evolution as a result of increasing numbers of patients being diagnosed as having microscopic sentinel node disease. Contemporary efforts are focused on defining the prognosis and natural history of this group. Through prognostic modeling using the number of nodes involved, ulceration status, and a measure of disease burden--disease in the sentinel node--relatively homogeneous subgroups can be identified. Long-term follow-up of patients staged with PCR molecular techniques on sentinel nodes shows conflicting value in assessing prognosis and therefore cannot be routinely used outside a clinical trial. The combination of genomic profiling using microarray analyses and the development of targeted therapy holds the future promise of individualizing prognosis and therapy.

Circulating Tyrosinase and MART-1 mRNA does not Independently Predict Relapse or Survival in Patients with AJCC Stage I–II Melanoma

The detection of melanoma cells in peripheral blood has been proposed to select patients with a high risk of relapse. In this study, tyrosinase and melanoma antigen recognized by T cells 1 (MART-1) mRNA expression was evaluated in serial samples obtained before definitive surgery and during follow-up in patients with American Joint Committee on Cancer stage I-II melanoma. Serial samples (n=2,262) were collected from 236 patients from 1997 to 2002. Analyses of the RNA samples were performed with a calibrated reverse transcriptase-PCR assay. Gender, age, primary tumor site, ulceration, thickness, Clark level, and histological subtype were analyzed together with tyrosinase and MART-1 mRNA treated as updated covariates in a Cox proportional-hazard model. After a median follow-up time of 66 months, 42 out of 236 patients (18%) had relapsed. The following variables were significantly associated with relapse-free survival in the univariate analyses: tyrosinase, MART-1, gender, ulceration, thickness, Clark level, and histological subtype. Entering these covariates into a multivariate Cox analysis resulted in thickness as the single independent prognostic factor (P<0.0001), whereas MART-1 (P=0.07) approached significance at the 5% significance level. The serial measurements of tyrosinase and MART-1 mRNA in peripheral blood of stage I-II melanoma patients cannot be demonstrated to have independent prognostic impact on relapse-free survival.

Circulating tumor cells: the 'leukemic phase' of solid cancers

It is well known that malignant cells circulate in the bloodstream of patients with solid tumors. However, the biological significance of circulating tumor cells (CTCs) and the clinical relevance of their detection are still debated. Besides technical issues regarding CTC-detection methods, discontinuous shedding of CTCs from established cancer deposits, genomic instability and metastatic inefficiency might underlie the conflicting results currently available. Nevertheless, technological advances and recent clinical findings are prompting researchers to dissect CTC biology further. Here, we review these recent findings, and discuss the prospects for the identification and molecular characterization of the CTC subset that is responsible for metastasis development. This would provide a formidable tool for prognosis evaluation, anticancer-drug development and, ultimately, cancer-therapy personalization.

Serial monitoring of circulating melanoma cells during neoadjuvant biochemotherapy for stage III melanoma: outcome prediction in a multicenter trial

PURPOSE

Circulating tumor cells (CTCs) in blood may be important in assessing tumor progression and treatment response. We hypothesized that quantitative real-time reverse transcriptase polymerase chain reaction using multimarker mRNA assays could detect CTCs and be used as a surrogate predictor of outcome in patients receiving neoadjuvant biochemotherapy (BC) for melanoma.

PATIENTS AND METHODS

Blood specimens were collected at four sampling points from 63 patients enrolled on a prospective multicenter phase II trial of BC before and after surgical treatment of American Joint Committee on Cancer stage III melanoma. Each specimen was assessed by quantitative real-time reverse transcriptase polymerase chain reaction for expression of four melanoma-associated markers: melanoma antigen recognized by T cells 1; beta1 --> 4-N-acetylgalactosaminyltransferase; paired box homeotic gene transcription factor 3; and melanoma antigen gene-A3 family, and the changes of CTCs during treatment and prognostic effect of CTCs after overall treatment on recurrence and survival were investigated.

RESULTS

At a median postoperative follow-up time of 30.4 months, 44 (70%) patients were clinically disease free. In relapse-free patients, the number of detected markers significantly decreased during preoperative BC (P = .036), during postoperative BC (P = .002), and during overall treatment (P < .0001). Marker detection after overall treatment was associated with significant decreases in relapse-free and overall survival (P < .0001). By multivariate analysis using a Cox proportional-hazards model, the number of markers detected after overall treatment was a significant independent prognostic factor for overall survival (risk ratio, 12.6; 95% CI, 3.16 to 50.5; P = .0003).

CONCLUSION

Serial monitoring of CTCs in blood may be useful for indicating systemic subclinical disease and predicting outcome of patients receiving neoadjuvant BC for metastatic melanoma.

Comparison between three molecular methods for detection of blood melanoma tyrosinase mRNA. Correlation with melanoma stages and S100B, LDH, NSE biochemical markers

BACKGROUND

The molecular monitoring of circulating tumor cells by reverse transcriptase-PCR (RT-PCR) for patients with melanoma, is still under debate. It may be affected by: a) pre-analytical variability, b) frequency of melanoma-associated gene transcripts and c) the reliability of the methods employed. Few commercial methods are available for the detection of tyrosinase mRNA in blood.

OBJECTIVE

Comparison between two RT-PCR-nested methods with a third one based on real-time methodology, for detection and quantitation of tyrosinase transcripts, respectively.

METHODS

Sixty-two melanoma patients with different AJCC stages and 20 healthy subjects were enrolled. All blood samples were extracted in duplicate with two different methods. Two nested-PCR methods (one commercial and one in house) plus a real time commercial kit were employed.

RESULTS

The two nested PCR methods employed were overimposable, specific and sensitive, at least in the stage III, where there was a concordance between sentinel lymph nodes detection and blood tyrosinase positivity. The different extraction methods did not affect the quality of results, while the commercial real-time kit cannot be used.

CONCLUSION

Tyrosinase mRNA detection may be therefore employed to monitor the melanoma patients over time in function of response to therapy.

Tumor cell and circulating markers in melanoma: Diagnosis, prognosis, and management

The search is on for biomarkers for use in the diagnosis, staging, prognosis, and management of patients with melanoma. As with many types of cancer, the hematogenous spread of melanoma is a bad prognostic sign, and many groups have attempted to detect circulating melanoma cells in patients with different stages of melanoma. Some studies have used direct extraction of intact tumor cells from the peripheral blood and others the detection of surrogate markers of circulating melanoma cells, such as tyrosinase or MART-1. However, a correlation between the detection of intact melanoma cells in the circulation and prognosis is controversial. Many other biomarkers have also been studied, including lactate dehydrogenase, S100, TA90, and C-reactive protein. Much progress has been made, and preliminary studies have shown promise with many of these markers. Finally, the detection of tumor-specific circulating DNA has shown promise as a prognostic and diagnostic marker of disease in melanoma as well. In this review we examine the most promising biomarkers for use in patients with cutaneous melanoma.