Prognostic value of circulating melanoma cells detected by reverse transcriptase-polymerase chain reaction

Epithelial-to-Mesenchymal Transition Gene Signature in Circulating Melanoma Cells: Biological and Clinical Relevance

The most promising method for monitoring patients with minimal morbidity is the detection of circulating melanoma cells (CMCs). We have shown that CD45^-CD146⁺ABCB5⁺ CMCs identify a rare primitive stem/mesenchymal CMCs population associated with disease progression. The epithelial-to-mesenchymal transition (EMT) confers cancer cells a hybrid epithelial/mesenchymal phenotype promoting metastatization. Thus, we investigated the potential clinical value of the EMT gene signature of these primitive CMCs. A reliable quantitative real-time polymerase chain reaction (qRT-PCR) protocol was settled up using tumor cell lines RNA dilutions. Afterwards, immune-magnetically isolated CMCs from advanced melanoma patients, at onset and at the first checkpoint (following immune or targeted therapy), were tested for the level of EMT hallmarks and EMT transcription factor genes. Despite the small cohort of patients, we obtained promising results. Indeed, we observed a deep gene rewiring of the EMT investigated genes: in particular we found that the EMT gene signature of isolated CMCs correlated with patients' clinical outcomes. In conclusion, We established a reliable qRT-PCR protocol with high sensitivity and specificity to characterize the gene expression of isolated CMCs. To our knowledge, this is the first evidence demonstrating the impact of immune or targeted therapies on EMT hallmark gene expressions in CMCs from advanced melanoma patients.

MCAM/MUC18/CD146 as a Multifaceted Warning Marker of Melanoma Progression in Liquid Biopsy

Human malignant melanoma shows a high rate of mortality after metastasization, and its incidence is continuously rising worldwide. Several studies have suggested that MCAM/MUC18/CD146 plays an important role in the progression of this malignant disease. MCAM/MUC18/CD146 is a typical single-spanning transmembrane glycoprotein, existing as two membrane isoforms, long and short, and an additional soluble form, sCD146. We previously documented that molecular MCAM/MUC18/CD146 expression is strongly associated with disease progression. Recently, we showed that MCAM/MUC18/CD146 and ABCB5 can serve as melanoma-specific-targets in the selection of highly primitive circulating melanoma cells, and constitute putative proteins associated with disease spreading progression. Here, we analyzed CD146 molecular expression at onset or at disease recurrence in an enlarged melanoma case series. For some patients, we also performed the time courses of molecular monitoring. Moreover, we explored the role of soluble CD146 in different cohorts of melanoma patients at onset or disease progression, rather than in clinical remission, undergoing immune therapy or free from any clinical treatment. We showed that MCAM/MUC18/CD146 can be considered as: (1) a membrane antigen suitable for identification and enrichment in melanoma liquid biopsy; (2) a highly effective molecular "warning" marker for minimal residual disease monitoring; and (3) a soluble protein index of inflammation and putative response to therapeutic treatments.

Spectrophotometric Assays for Sensing Tyrosinase Activity and Their Applications

Tyrosinase (TYR, E.C. 1.14.18.1), a critical enzyme participating in melanogenesis, catalyzes the first two steps in melanin biosynthesis including the ortho-hydroxylation of L-tyrosine and the oxidation of L-DOPA. Previous pharmacological investigations have revealed that an abnormal level of TYR is tightly associated with various dermatoses, including albinism, age spots, and malignant melanoma. TYR inhibitors can partially block the formation of pigment, which are always used for improving skin tone and treating dermatoses. The practical and reliable assays for monitoring TYR activity levels are very useful for both disease diagnosis and drug discovery. This review comprehensively summarizes structural and enzymatic characteristics, catalytic mechanism and substrate preference of TYR, as well as the recent advances in biochemical assays for sensing TYR activity and their biomedical applications. The design strategies of various TYR substrates, alongside with several lists of all reported biochemical assays for sensing TYR including analytical conditions and kinetic parameters, are presented for the first time. Additionally, the biomedical applications and future perspectives of these optical assays are also highlighted. The information and knowledge presented in this review offer a group of practical and reliable assays and imaging tools for sensing TYR activities in complex biological systems, which strongly facilitates high-throughput screening TYR inhibitors and further investigations on the relevance of TYR to human diseases.

Relevance of circulating hybrid cells as a non-invasive biomarker for myriad solid tumors

Metastatic progression defines the final stages of tumor evolution and underlies the majority of cancer-related deaths. The heterogeneity in disseminated tumor cell populations capable of seeding and growing in distant organ sites contributes to the development of treatment resistant disease. We recently reported the identification of a novel tumor-derived cell population, circulating hybrid cells (CHCs), harboring attributes from both macrophages and neoplastic cells, including functional characteristics important to metastatic spread. These disseminated hybrids outnumber conventionally defined circulating tumor cells (CTCs) in cancer patients. It is unknown if CHCs represent a generalized cancer mechanism for cell dissemination, or if this population is relevant to the metastatic cascade. Herein, we detect CHCs in the peripheral blood of patients with cancer in myriad disease sites encompassing epithelial and non-epithelial malignancies. Further, we demonstrate that in vivo-derived hybrid cells harbor tumor-initiating capacity in murine cancer models and that CHCs from human breast cancer patients express stem cell antigens, features consistent with the potential to seed and grow at metastatic sites. Finally, we reveal heterogeneity of CHC phenotypes reflect key tumor features, including oncogenic mutations and functional protein expression. Importantly, this novel population of disseminated neoplastic cells opens a new area in cancer biology and renewed opportunity for battling metastatic disease.

CTCs as a prognostic and predictive biomarker for stage II/III Colon Cancer: a companion study to the PePiTA trial

BACKGROUND

Adjuvant therapy improves the prognosis of stage II & III colon cancer patients. Unfortunately, most patients do not benefit from this treatment. PePITA (NCT00994864) is a prospective, multicenter, non-randomized study whose primary objective is to predict the outcome of adjuvant therapy in colon cancer.

METHODS

The primary objective was to determine the prognostic and predictive value of circulating tumor cell (CTC) detection before therapy and after one course of preoperative FOLFOX.

RESULTS

Out of the 58 first patients accrued in PePiTA trial, 36 patients participated in the CTC companion study, of whom 32 had at least one evaluable sample. Only 5 patients (14, 95% CI = 5-30%) had ≥1 CTC/22.5 ml blood in at least one of the two timepoints with 2 patients having ≥1 CTC/22.5 ml at baseline (6, 95% CI: 1-19%). The detection rate of patients with CTCs at baseline being lower than expected, the inclusion of patients in the PePiTA CTC substudy was stopped. The limited sample size did not allow us to investigate the prognostic and predictive value of CTCs in locally advanced colon cancer.

CONCLUSIONS

Our data illustrate the need for further standardized studies in order to find the most reliable prognostic/predictive biomarker in early-stage colon cancer.

TRIAL REGISTRATION

This trial was prospectively registered at Jules Bordet institute ( NCT00994864 ) on the October 14, 2009.

Liquid biomarkers in melanoma: detection and discovery

A vast array of tumor-derived genetic, proteomic and cellular components are constantly released into the circulation of cancer patients. These molecules including circulating tumor DNA and RNA, proteins, tumor and immune cells are emerging as convenient and accurate liquid biomarkers of cancer. Circulating cancer biomarkers provide invaluable information on cancer detection and diagnosis, prognosticate patient outcomes, and predict treatment response. In this era of effective molecular targeted treatments and immunotherapies, there is now an urgent need to implement use of these circulating biomarkers in the clinic to facilitate personalized therapy. In this review, we present recent findings in circulating melanoma biomarkers, examine the challenges and promise of evolving technologies used for liquid biomarker discovery, and discuss future directions and perspectives in melanoma biomarker research.

Macrophage depletion reduces postsurgical tumor recurrence and metastatic growth in a spontaneous murine model of melanoma

Surgical resection of tumors is often followed by regrowth at the primary site and metastases may emerge rapidly following removal of the primary tumor. Macrophages are important drivers of tumor growth, and here we investigated their involvement in postoperative relapse as well as explore macrophage depletion as an adjuvant to surgical resection. RETAAD mice develop spontaneous metastatic melanoma that begins in the eye. Removal of the eyes as early as 1 week of age did not prevent the development of metastases; rather, surgery led to increased proliferation of tumor cells locally and in distant metastases. Surgery-induced increase in tumor cell proliferation correlated with increased macrophage density within the tumor. Moreover, macrophages stimulate tumor sphere formation from tumor cells of post-surgical but not control mice. Macrophage depletion with a diet containing the CSF-1R specific kinase inhibitor Ki20227 following surgery significantly reduced postoperative tumor recurrence and abrogated enhanced metastatic outgrowth. Our results confirm that tumor cells disseminate early, and show that macrophages contribute both to post-surgical tumor relapse and growth of metastases, likely through stimulating a population of tumor-initiating cells. Thus macrophage depletion warrants exploration as an adjuvant to surgical resection.

Sequential molecular analysis of circulating MCAM/MUC18 expression: a promising disease biomarker related to clinical outcome in melanoma

MCAM/MUC18 is a cell adhesion molecule associated with higher incidence of relapse in melanoma. The purpose of our study was to evaluate its role as a promising disease biomarker of progression through sequential molecular MCAM/MUC18 RT-PCR assay on serial blood samples collected during the clinical follow-up of 175 melanoma patients in different American Joint Committee on Cancer (AJCC) stages. MCAM/MUC18 molecular detection, found at least once in 22 out of the 175 patients, was significantly associated with poor prognosis and death (p < 0.001), regardless of the AJCC stages. Positive expression, either if primarily present or later acquired, was associated with melanoma progression, whereas patients primarily negative or with subsequent loss gained clinical remission or stable disease, even if in advanced stages (p < 0.005). Six AJCC advanced stages always MCAM/MUC18 negative are in complete remission or with a stable disease (p < 0.007). Semiquantitative immunohistochemical MCAM/MUC18 staining on corresponding primary melanomas was related to peripheral molecular expression. Correlations between circulating molecular and tissutal immunohistochemical detection, primary tumour thickness, AJCC stages and clinical outcome were statistically evaluated using Student's t test, ANOVA, Spearman's rank correlation test, Pearson χ (2)-test and McNemar's test. In our investigation, MCAM/MUC18 expression behaves as a "molecular warning of progression" even in early AJCC patients otherwise in disease-free conditions. Achievement of this molecule predicted the emergence of a clinically apparent status, whereas absence or persistent loss was related to a stable disease or to a disease-free status. If confirmed in larger case series, MCAM/MUC18 molecular expression could predict good or poor clinical outcome, possibly becoming a promising prognostic factor.

Detection methods of circulating tumor cells in cutaneous melanoma: a systematic review

The vast majority of melanoma-related deaths are due to disseminated malignancy. Many treated patients who are clinically disease-free will go on to relapse. Therefore, new prognostic tools must be developed to better assess metastatic potential and assist in patient management. Circulating tumor cells are a widely studied metastatic biomarker with promising prognostic utility, as the shedding of cells from the primary tumor into peripheral blood is a necessary step in disease dissemination. An assortment of technologies and techniques has been developed to isolate and detect circulating melanoma cells (CMCs), but a standardized method is yet to be established. It is the aim of this study to systematically review the diverse enrichment and detection methods of circulating tumor cells in cutaneous melanoma. A literature search yielded 351 articles, of which 74 were deemed eligible according to inclusion criteria, the primary requirement being the reporting of patient CMC positivity status stratified by the stage of melanoma. Pertinent studies were used to evaluate the advantages and disadvantages of each method. Additionally, we calculated the sensitivity and specificity of seven common melanoma-associated markers based on the available literature.

Binding and isolation of tumor cells in biological media with perfluorocarbon microbubbles

With the emerging interest in personalized medicine, there is strong demand for new technologies for clinical sample interrogation. Exfoliated tumor cells in variety of pathological samples (e.g., blood, bone marrow, urine) could provide invaluable information for diagnosis and prognosis of cancers. Here we describe a detailed method for capture and isolation of tumor cells in medium, blood, or large issue buffy coat using EpCAM-targeted buoyant microbubbles (MBs). Perflorohexane gas lipid shell MBs were prepared with emulsification method and conjugated with antibody as described by us before [25]. The binding of EpCAM-targeted MBs to A549 (human lung carcinoma) and 4T1 (mouse breast carcinoma) cells spiked into BSA/PBS or blood was more than 90%, which was comparable with commercial anti-EpCAM immunomagnetic beads (DynaBeads). Anti-EpCAM MBs efficiently (75-82%) isolated BxPC3 pancreatic tumor cells spiked into medium, blood or a buffy coat, within 15-30 min of incubation. We discuss MB parameters and experimental conditions critical to achieve efficient cells binding and isolation. In conclusion, MB-assisted cell isolation is a promising method for rapid enrichment of cells and biomarkers from biological samples.

Assessment of prognostic circulating tumor cells in a phase III trial of adjuvant immunotherapy after complete resection of stage IV melanoma

OBJECTIVE

To verify circulating tumor cell (CTC) prognostic utility in stage IV resected melanoma patients in a prospective international phase III clinical trial.

BACKGROUND

Our studies of melanoma patients in phase II clinical trials demonstrated prognostic significance for CTCs in patients with AJCC stage IV melanoma. CTCs were assessed to determine prognostic utility in follow-up of disease-free stage IV patients pre- and during treatment.

METHODS

After complete metastasectomy, patients were prospectively enrolled in a randomized trial of adjuvant therapy with a whole-cell melanoma vaccine, Canvaxin, plus Bacille Calmette-Guerin (BCG) versus placebo plus BCG. Blood specimens obtained pretreatment (n = 244) and during treatment (n = 214) were evaluated by quantitative real-time reverse-transcriptase polymerase chain reaction (qPCR) for expression of MART-1, MAGE-A3, and PAX3 mRNA biomarkers. Univariate and multivariate Cox analyses examined CTC biomarker expression with respect to clinicopathological variables.

RESULTS

CTC biomarker(s) (≥ 1) was detected in 54% of patients pretreatment and in 86% of patients over the first 3 months. With a median follow-up of 21.9 months, 71% of patients recurred and 48% expired. CTC levels were not associated with known prognostic factors or treatment arm. In multivariate analysis, pretreatment CTC (> 0 vs. 0 biomarker) status was significantly associated with disease-free survival (DFS; HR 1.64, P = 0.002) and overall survival (OS; HR 1.53, P = 0.028). Serial CTC (>0 vs. 0 biomarker) status was also significantly associated with DFS (HR 1.91, P = 0.02) and OS (HR 2.57, P = 0.012).

CONCLUSION

CTC assessment can provide prognostic discrimination before and during adjuvant treatment for resected stage IV melanoma patients.

Circulating tumor cells in uveal melanoma

Despite advances in the diagnosis and local tumor control, the overall mortality rate for uveal melanoma remains high because of the development of metastatic disease. The clinical and histopathological systems currently being used to classify patients are not sufficiently accurate to predict metastasis. Tumor genotyping has demonstrated significant promise but obtaining tumor tissue can be problematic. Furthermore, assessment of tumor tissue does not indicate whether tumor cells have actually been shed and cannot indicate whether treatment is reducing metastasis. The detection of circulating tumor cells in blood has been shown to be a prognostic biomarker that can be used to monitor the effectiveness of therapy in patients with metastatic carcinoma. Uveal melanoma disseminates hematogenously, and the detection of circulating melanoma cells may potentially be useful for diagnosis, risk stratification, and the monitoring of disease progression and treatment efficacy. PCR-based and immunomagnetic cell isolation techniques, derived from studies in patients with cutaneous melanoma, have been tested. For various biological and technical reasons, they have not demonstrated the accuracy and reproducibility required for an effective prognostic assay in patients with uveal melanoma. Assessments have been confounded by false positives and negatives and thus, correlations between circulating melanoma cells and survival have not yet been established. Circulating melanoma cell detection is a valuable tool for investigating metastasis in uveal melanoma and also has the potential to become a standard part of uveal melanoma management. However, more research on the biology of uveal melanoma as well as improvements upon the current technologies are needed.

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.

Circulating tumor cells in melanoma: a review of the literature and description of a novel technique

Melanoma is a prevalent and deadly disease with limited therapeutic options. Current prognostic factors are unable to adequately guide treatment. Circulating tumor cells are a disease-specific factor that can be used as a prognostic variable to guide therapy. Most research to date has focused on identification of circulating tumor cells using various methods, including polymerase chain reaction. These techniques, however, have poor sensitivity and variable specificity and predictive significance. A recently developed technology to identify circulating tumor cells is the CellSearch system. This system uses immunomagnetic cell labeling and digital microscopy. This technology may provide an alternative method to identify circulating tumor cells in patients with advanced-stage melanoma and function as a prognostic factor. We review the literature on circulating tumor cells in melanoma and present data collected at our institution using the CellSearch system in nine patients with stage III or IV melanoma.

Detection of melanoma-derived cancer-testis antigen CT16 in patient sera by a novel immunoassay

Cancer-testis antigens (CTAs) are expressed mainly in various cancer tissues and in testis or placenta. Because of their restricted expression pattern, the CTAs can be potentially used for vaccine development and diagnostic applications. CTA CT16 has been found to be expressed in lung and renal cancers as well as in melanomas. Detection of CT16 protein directly from patient serum could facilitate monitoring of tumor growth and response to therapy in CT16-positive patients. A highly sensitive time-resolved fluorescence-based immunoassay measuring CTA CT16 in serum was developed. Generally, CTAs have not been measured directly from body fluids. CT16 level was detectable in 14 of 23 (61%) patients with metastatic melanoma, whereas none of the nine healthy volunteers collected by us had measurable CT16 level. For an unknown reason, 1 of 20 commercial control serum samples gave a positive result. The Wilcoxon-Mann-Whitney exact test showed statistically significant difference when patients with metastatic melanoma were compared to our control group (p = 0.006) or to the commercial set (p < 0.001). Four melanoma patients had exceptionally high serum CT16 level. CT16 did not correlate either with S100B, a recognized marker of progressing melanoma, or with unspecific serum marker lactate dehydrogenase. Elevation of CT16 titers preceded or followed the clinical diagnosis of disease progression in four patients with metastatic melanoma. As a conclusion, our results show that CT16 protein can be measured directly from patient serum, and the developed assay has a potential for clinical use.

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.

Prognostic value of microphthalmia-associated transcription factor and tyrosinase as markers for circulating tumor cells detection in patients with melanoma

The aim of this study was to analyze microphthalmia-associated transcription factor (MITF) as a marker for the detection of circulating melanoma cells, determine its prognostic value in melanoma patients, and compare it with tyrosinase. Blood samples from 201 melanoma patients in all stages of the disease and 40 healthy volunteers were analyzed. RNA was isolated from mononuclear cell fraction of the blood and assayed by reverse transcription-PCR for the expression of MITF and tyrosinase. All samples from healthy volunteers were negative for both MITF and tyrosinase. Out of 201 blood samples from melanoma patients 32 were positive for MITF, 20 for tyrosinase, and four for both MITF and tyrosinase. Analysis of MITF as an additional marker to tyrosinase allowed for detection of circulating melanoma cells in a larger number of melanoma patients in comparison to tyrosinase analysis alone (48 vs. 20 positive). A positive value of MITF was associated with shorter progression-free (P=0.005) and overall survival (P=0.042). A positive value of tyrosinase was associated with shorter overall survival (P=0.012), whereas there was no significant association between the value of tyrosinase and progression-free survival. The value of MITF was selected with multivariate analysis as the independent prognostic factor for progression-free survival, whereas the only independent prognostic factor for overall survival was the stage of disease. This study has shown that MITF is a specific marker for detection of circulating melanoma cells that has a prognostic value in melanoma patients. Determination of MITF in addition to tyrosinase improved the detection of circulating melanoma cells in melanoma patients.

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.

Old and new serological biomarkers in melanoma: where we are in 2009

Biomarkers play an important role in the diagnosis and prognostic classification of various cancers and can be useful in monitoring the patient's clinical course of disease and response to therapy. Generally, biomarkers are proteins and their expressions are associated with malignant disease. In the majority of cases, the marker molecules are expressed by the tumour cells themselves or by the tumour microenvironment cells. Thus, most biomarkers can primarily be found in malignant tissues, but after active secretion or passive release at tumour destruction, they become detectable in body fluids such as blood. Besides morphological and histopathological biomarkers (anatomic site, type of the primary tumour, tumour size, invasion depth, vascular invasion and ulceration), an increasing variety of serological markers have been identified, providing the possibility of a more detailed diagnostic and prognostic subgrouping of tumour entities, up to and even changing existing classification systems. The goal of this review is to provide an overview of old and more recent serological biomarkers in malignant melanoma. We will first focus on confirmed and nonconfirmed serum tumour markers, followed by proteomic profiling, an innovative approach to identify new and better serological biomarkers in melanoma, and ending with the predictive factors for treatments in this pathology.

Biomarkers of metastatic melanoma

Melanoma, one of the most aggressive forms of human cancer, has undergone an alarming increase in incidence in recent years. Early detection is a prerequisite for proper diagnosis and therapy orientation. Soluble biomarkers are an important tool for early diagnosis. Markers that are associated with melanocyte functions imply the enzymes involved in melanin synthesis and the melanin-related metabolites. Proteins such as autocrine melanocyte cell growth factor and melanoma metastasis suppressor have gained attention in the biomarkers domain. The antimelanoma immune response elicited in patients can not only provide new biomarkers but important therapeutic approaches in specific treatments. All the molecules generated during the metastasis process, invasion of neighboring tissue, angiogenesis, invading lymphatic/blood vessels and establishing new tumors at a distant site, are targets for biomarker discovery.

Disseminated and circulating tumor cells: Role in effective cancer management

Dissemination of tumor cells from primary tumors in the circulatory system is an early event in carcinogenesis. The presence of these single disseminated tumor cells (DTC) in peripheral blood, bone marrow and distant organs is the rationale for adjuvant systemic treatment. Detection of DTC in bone marrow aspirates from breast cancer patients and other solid tumors at the primary diagnosis impacts the prognosis of disease. In peripheral blood these cells are termed as circulating tumor cells (CTC). Due to technical difficulties the clinical significance of CTC detection at early stages is less established. This review focuses on available techniques for detection of DTC and CTC, recent technical advances in development of more sensitive microfluidic methods for capture of DTC and CTC and possibilities for further detection and their potential molecular characterization. Not only the clinical significance of DTC but also the presence of cancer stem cells in dissemination clearly demonstrates the need for development of sensitive technologies allowing for definition of biomarkers and molecular targets on cells in dissemination, thus eventually leading to optimization of systemic therapies.

Tumor cells disseminate early, but immunosurveillance limits metastatic outgrowth, in a mouse model of melanoma

Although metastasis is the leading cause of cancer-related death, it is not clear why some patients with localized cancer develop metastatic disease after complete resection of their primary tumor. Such relapses have been attributed to tumor cells that disseminate early and remain dormant for prolonged periods of time; however, little is known about the control of these disseminated tumor cells. Here, we have used a spontaneous mouse model of melanoma to investigate tumor cell dissemination and immune control of metastatic outgrowth. Tumor cells were found to disseminate throughout the body early in development of the primary tumor, even before it became clinically detectable. The disseminated tumor cells remained dormant for varying periods of time depending on the tissue, resulting in staggered metastatic outgrowth. Dormancy in the lung was associated with reduced proliferation of the disseminated tumor cells relative to the primary tumor. This was mediated, at least in part, by cytostatic CD8+ T cells, since depletion of these cells resulted in faster outgrowth of visceral metastases. Our findings predict that immune responses favoring dormancy of disseminated tumor cells, which we propose to be the seed of subsequent macroscopic metastases, are essential for prolonging the survival of early stage cancer patients and suggest that therapeutic strategies designed to reinforce such immune responses may produce marked benefits in these patients.

Predicting outcome in melanoma: where are we now?

Melanoma incidence continues to rise in most countries. This is of grave concern, given the mortality rate in a relatively young population. Current staging tools are limited in their ability to predict accurately those at risk of metastatic disease, relapse and treatment failure. This overview comprehensively reviews relevant literature, with the focus on the last 5 years, and discusses the current state of traditional and emerging novel methods of staging for melanoma and their effect on prognosis in this population.

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.

Melanoma-associated markers expression in blood: MUC-18 is associated with advanced stages in melanoma patients

BACKGROUND

Multimarker reverse transcriptase-polymerase chain reaction (RT-PCR) was originally reported to reveal melanoma-associated mRNAs (MAMs) in melanoma cells but not in the peripheral blood of healthy individuals.

OBJECTIVES

To evaluate the expression of MAMs in the peripheral blood of melanoma patients at different American Joint Committee on Cancer (AJCC) stages, and to correlate their presence with early and/or advanced stages of the disease.

MATERIALS AND METHODS

One hundred blood samples of melanoma patients (AJCC I-IV) were analysed using multimarker RT-PCR to assess the co-expression of Tyr-OH, MART-1, MAGE-3, MUC-18/MCAM and p97. Patients were stratified into two disease categories: early and advanced stages. The former includes in situ and melanoma stages AJCC I-II, the latter AJCC III-IV. chi(2) and Fisher's exact tests were used to statistically evaluate the association between each MAM and disease categories. The recognized significant associations were subsequently resubmitted to univariate logistic regression. Furthermore, sensitivity and specificity were established.

RESULTS

At least one MAM could be detected in 24% of our series. Tyr-OH was the most common marker (14%), followed by MUC-18 (12%), MART-1 (5%), MAGE-3 (4%) and p97 (3%). No significant association among Tyr-OH, MART-1, MAGE-3, p97 and disease stages were evidenced. Only MUC-18 was statistically associated (P < 0.009) with advanced stages alone or co-expressed with other MAMs. According to logistic regression univariate analysis, MUC-18 increases the probability (odds ratio: 33) being in advanced stages and the incidence of recurrences (95% CI 2.9-374).

CONCLUSIONS

MUC-18 RT-PCR assay could be proposed as an adjunctive molecular method in the management of melanoma patients and is useful in the monitoring of study protocols.

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 micrometastases of esophageal cancer detected by carcinoembryonic antigen mRNA reverse transcriptase-polymerase chain reaction: clinical implications

In some patients without distant metastases according to conventional preoperative investigations, relapse occurs in distant organs within a few years after radical resection of esophageal cancer. Various attempts have been made to detect micrometastases that are not found by conventional techniques. A quantitative real-time reverse-transcriptase polymerase chain reaction was used to detect messenger RNA for carcinoembryonic antigen in 147 blood samples from 49 patients scheduled for radical resection of esophageal cancer at Juntendo University Hospital between September 2003 and June 2004. The number of circulating cancer cells was assessed and the clinical significance of detecting such micrometastases was analyzed. Multivariate analysis showed that positivity of this assay was significantly associated with pT1 or pT2 disease and stage III or stage IV disease. Patients with more than 40-50 carcinoembryonic antigen mRNA copies among 10(4) normal cells on quantitative analysis had a higher recurrence rate. The number of tumor cells circulating in the blood may have more influence on the prognosis of esophageal cancer than the presence of tumor cells.

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.

Prognostic role of circulating melanoma cells detected by reverse transcriptase-polymerase chain reaction for tyrosinase mRNA in patients with melanoma

A need for factors predictive of prognosis is present in patients who are diagnosed with malignant melanoma. The detection of circulating melanoma cells by reverse transcriptase-polymerase chain reaction for tyrosinase mRNA is a possible negative prognostic factor. The aim of this study was to assess the prognostic value of reverse transcriptase-PCR for tyrosinase mRNA in peripheral blood samples. From January 2000 to February 2003, duplicate blood samples were drawn from 114 melanoma patients following surgery and informed consent, and were tested with reverse transcriptase-PCR, for tyrosinase mRNA. Outer primers for the first PCR were R1 (sense): TTGGCAGATTGTCTGTAGCC and R2 (antisense): AGGCATTGTGCATGCTGCT. For the second round of PCR, nested primers were R3 (sense): GTCTTTATGCAATGGAACGC and R4 (antisense): GCTATCCCAGTAAGTGGACT. Threshold for detection of the technique was determined by adding serially diluted MelJuSo cells to healthy volunteer blood samples. Overall, 91 (79.1%) patients tested negative for tyrosinase mRNA and 24 (20.9%) tested positive. The number of patients who tested positive by stage was 3/38 (7.9%) for stage I, 3/22 (13.6%) for stage II, 5/30 (16.7%) for stage III and 13/24 (54.2%) for stage IV (P< 0.0001). 11/90 (12.2%) patients with no evidence of disease (stage I, II and III) tested positive and 13/24 (54.2%) patients with clinically confirmed distant metastases (stage IV) tested positive (P<0.00001). With median follow-up of 372 days or to death (range: 0-1303 days), median progression-free survival has not been reached for tyrosinase-negative patients and was 265 days for tyrosinase-positive patients (P<0.00001, log-rank test=21.07). Median overall survival was 344 days for tyrosinase-positive patients and has not been reached for tyrosinase-negative patients (P=0.0001, log-rank test=21.38). Stage, Breslow thickness and result of RT-PCR were significant prognostic factors for disease-free survival in a multivariate analysis, and stage was the only significant prognostic factor for overall survival. In conclusion, detection of circulating melanoma cells by reverse transcriptase-PCR for tyrosinase mRNA is a significant adverse prognostic factor for disease-free survival in patients with malignant melanoma.

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.

Prognostic relevance of baseline and sequential peripheral blood tyrosinase expression in 200 consecutive advanced metastatic melanoma patients

The relationship between the disease course and the prognostic relevance of sequential tyrosinase reverse transcription-PCR assay in the peripheral blood of advanced metastatic melanoma patients was ascertained. The clinical usefulness of tyrosinase in stage IV melanoma patients is still debated, owing to the wide range of variability (positive expression from 30 up to 100% of patients) and the possibility of a transient shedding of melanoma cells into the bloodstream. A total of 200 consecutive stage IV metastatic patients treated at our department were included, 149 with active metastatic disease undergoing systemic therapies (group A), and 51 disease free after surgery (group B). For each patient, a baseline sample was obtained within 3 weeks of either the clinical/radiological demonstration of metastatic disease or the surgical treatment; thereafter, tyrosinase determinations were performed at day 1 of each therapy course before chemotherapy administration or at each follow-up visit. Tyrosinase expression was determined using standard reverse transcription-PCR nested techniques. A baseline positive determination was obtained in 72.5% of the patients with active metastatic disease (group A) but not in any of the patients who were disease free after surgery (group B). Therapy administration induced an early clearance of circulating melanoma cells, from 72.5 to 44.9% at the second down to 29.5% at the third determination. Tyrosinase expression before the third cycle was significantly associated with the clinical response: 56/81 (69.1%) patients with a negative tyrosinase determination obtained a response or a stable disease, whereas 29/34 (85.3%) patients with a positive test developed a progressive disease (P<0.001). A clinical response was observed in all the patients who had a negative tyrosinase at the first three determinations, although all patients whose first three determinations were positive developed a progressive disease. Multivariate analysis showed that baseline tyrosinase status carries an independent prognostic value on both overall survival and time to progression; moreover, tyrosinase results during follow-up were entered as time-dependent covariates in a multivariate analysis and were shown to be the most significant prognostic parameter associated to both overall survival and time to progression. In particular, the presence of a constant positive expression during follow-up was associated with the development of new metastatic sites in 95.6% of patients with active metastatic disease. Our results demonstrate that the discrepancies in the positive tyrosinase rates reported in the literature are related to the disease status at the time of sampling and to chemotherapy administration. Tyrosinase expression in the peripheral blood both at baseline and during follow-up can be considered a reliable prognostic parameter associated with the response to treatment, development of new metastatic sites, time to progression and survival.

Sequence variability of retroviral particles derived from human melanoma cells

We have shown that melanoma cells produce viral particles that contain sequences which are homologous to human endogenous retroviruses. In this study particles derived from different melanoma cell lines and from melanoma cells of a lymph node metastasis were characterized. We determined the density and the reverse transcriptase (RT) activity of viral particles. Furthermore, we analyzed the sequence variability of multiple clones of each particle preparation. The particles were found to package sequences, which vary for each of the analyzed cell lines. Moreover, even particles derived from the same cell line contain heterologous sequences.

Serial detection of circulating tumour cells by reverse transcriptase-polymerase chain reaction assays is a marker for poor outcome in patients with malignant melanoma

Background

Detection of circulating malignant cells (CMCs) through a reverse transcriptase-polymerase chain reaction (RT-PCR) assay seems to be a demonstration of systemic disease. We here evaluated the prognostic role of RT-PCR assays in serially-taken peripheral blood samples from patients with malignant melanoma (MM).

Methods

One hundred forty-nine melanoma patients with disease stage ranging from I to III were consecutively collected in 1997. A multi-marker RT-PCR assay was used on peripheral blood samples obtained at time of diagnosis and every 6 months during the first two years of follow-up (total: 5 samples). Univariate and multivariate analyses were performed after 83 months of median follow-up.

Results

Detection of at least one circulating mRNA marker was considered a signal of the presence of CMC (referred to as PCR-positive assay). A significant correlation was found between the rate of recurrences and the increasing number of PCR-positive assays (P = 0.007). Presence of CMC in a high number (≥2) of analysed blood samples was significantly correlated with a poor clinical outcome (disease-free survival: P = 0.019; overall survival: P = 0.034). Multivariate analysis revealed that presence of a PCR-positive status does play a role as independent prognostic factors for overall survival in melanoma patients, adding precision to the predictive power of the disease stage.

Conclusion

Our findings indicated that serial RT-PCR assay may identify a high risk subset of melanoma patients with occult cancer cells constantly detected in blood circulation. Prolonged presence of CMCs seems to act as a surrogate marker of disease progression or a sign of more aggressive disease.

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.

Molecular diagnostics in melanoma

Molecular pathology is rapidly evolving, featuring continuous technologic improvements that offer novel clinical opportunities for the recognition of disease predisposition, for identifying sub-clinical disease, for more accurate diagnosis, for selecting efficacious and non-toxic therapy, and for monitoring of disease outcome. Currently, the identification and prognosis of primary cutaneous melanoma is based on histologic factors (tumor depth and ulceration) and clinical factors (number of lymph node and/or distant metastases). However, metastasis can occur in patients with thin melanomas, and sentinel lymph node biopsy does not identify all patients at risk for distant metastasis. New markers exist that correlate with melanoma progression, which may aid in melanoma identification, prognostication, and detection of minimal residual disease/early recurrence. Moreover, not many therapeutic options exist for melanoma as no regimen prolongs survival. Emerging data with investigational therapies suggest that certain markers might play a crucial role in identifying patients who will respond to therapy or show utility in the monitoring the response to therapy. Herein, molecular diagnostics that can potentially benefit the individual melanoma patient will be discussed.

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.

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.

Lack of Prognostic Importance of Reverse-Transcriptase Polymerase Chain Reaction Detection of Circulating Messenger RNA in Patients with Melanoma

BACKGROUND

Molecular serologic markers for detecting early melanoma metastases have been described. The objective of this study was to determine whether reverse-transcriptase polymerase chain reaction detection of circulating tyrosinase messenger RNA (mRNA) can identify the presence of subclinical metastases and predict subsequent clinical recurrence in surgically treated melanoma patients who are at significant risk for relapse.

METHODS

Preoperative peripheral blood samples of disease-free melanoma patients, disease stage ranging from I to IV, were analyzed for the presence of tyrosinase mRNA by semiquantitative reverse-transcriptase polymerase chain reaction as a putative marker for circulating melanoma cells. Multivariate analysis was performed to evaluate the prognostic value of tyrosinase mRNA in the blood and in the correlating pathologic stage of disease with recurrence and survival.

RESULTS

The study group consisted of 96 patients. The mean age was 54 years (range, 24 to 83 years). The mean Breslow thickness was 3 mm (range, 0.9 to 21 mm). Circulating melanoma cells were detected in 66 patients (69 percent). Blood polymerase chain reaction positivity by American Joint Committee on Cancer stage was as follows: stage I, 19 of 28 patients (68 percent); stage II, 17 of 25 patients (68 percent); stage III, 28 of 41 patients (68 percent); and stage IV, two of two patients (100 percent). Tyrosinase detection was not associated with stage of disease (p = 0.77). At a median follow-up of 30 months, disease recurred in 21 patients (22 percent), and 15 patients (16 percent) died. Disease stage of the patients correlated with recurrence (p < 0.0001) and death (p < 0.0001). The finding of mRNA tyrosinase in peripheral blood samples was not associated with recurrence (p = 0.1) or death (p = 0.77).

CONCLUSIONS

The use of polymerase chain reaction to detect circulating tyrosinase mRNA in peripheral blood does not correlate with traditional prognostic indicators in patients with cutaneous melanoma and does not appear to be an effective prognostic tool.

Biomarkers for melanoma

PURPOSE OF REVIEW

Given the capricious nature of melanoma, biomarkers that provide significant insight into the behavior of melanoma would greatly aid in identifying patients at risk for disease progression, those whose disease has progressed subclinically, and those who would benefit from currently available systemic therapies. This review focuses on molecular prognostic markers in primary melanoma, markers that aid in the detection of metastatic melanoma, and markers predictive of systemic therapy.

RECENT FINDINGS

Significant advances have been made in the field of melanoma biomarkers. Utilization of paraffin-embedded tissue and multiple markers have improved the RT-PCR assays for detection of melanoma cells in lymph node tissue as well as peripheral blood. Lymphangiogenesis has been identified as a novel mechanism for melanoma progression, and candidate markers in the NF-kappaB signaling pathway have been identified to play a key role in melanoma: tumor vasculature interactions. Loss of heterozygosity has been used to identify potential candidates for biochemotherapy. Furthermore, serum S100B protein has been shown to be superior to lactate dehydrogenase in predicting prognosis and response to treatment for patients with advanced melanoma.

SUMMARY

Although recent studies have contributed greatly to the development of melanoma markers, it is anticipated that the application of gene expression profiling and proteomics techniques to melanocytic neoplasms will result in the identification of even more effective biomarkers for melanoma than those currently in clinical use.