Prognostic significance of detecting micrometastases by tyrosinase RT/PCR in sentinel lymph node biopsies: lessons from 322 consecutive melanoma patients

Role of CD14-positive cells in inflammatory cytokine and pain-related molecule expression in human degenerated intervertebral discs

Multiple human and animal studies suggest that the upregulation of inflammatory cytokines and other pain-related molecules in degenerated or injured intervertebral discs (IVDs) may cause discogenic low back pain (LBP). We previously reported that macrophages in injured IVD in mice produced inflammatory cytokines, but not other pain-related molecules. CD14 is a monocyte marker expressed mainly by macrophages. The aim of the current study was to evaluate the role of CD14-positive cells in inflammatory cytokine and pain-related molecule expression in human degenerated IVD. IVD samples were harvested from 14 patients, including 10 with lumbar spinal stenosis, four with adult spinal deformity, and one with lumbar disc herniation during spinal interbody fusion surgery. Harvested IVD-derived mononuclear cells were obtained and CD14-positive (+) and CD14-negative (-) cells were separated using CD14 antibody and streptavidin-labeled magnetic beads. Inflammatory cytokines messenger RNA (mRNA) in the CD14(+) and CD14(-) cells, including tumor necrosis factor ɑ (TNFA), in, terleukin-1β (IL1B) and IL6, were determined using quantitative polymerase chain reaction (qPCR) and their expression levels were compared. To evaluate factors controlling the regulation of pain-related molecules mRNA expression, cultured CD14(-) and CD14(+) cells from IVDs were stimulated with recombinant human TNF-ɑ and IL-1β and levels of pain-related molecules, including calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) were determined using qPCR. Levels of TNFA, IL1B, IL6, and NGF in CD14(+) cells were significantly increased compared with those in CD14(-) cells (TNFA, p = 0.006; IL1B, p = .017; IL6, p = .010; NGF, p = .027). Following TNFA stimulation, NGF levels were significantly increased in CD14(-) and CD14(+) cells (CD14(-), p = .003; CD14(+), p < .001) and CGRP was significantly increased in CD14(-) IVD cells (p = .040). Following IL1B stimulation, NGF levels were significantly increased in CD14(-) cells (p = .004). CD14(+) cells had higher TNFA, IL1B, IL6, and NGF expressions than CD14(-) cells in human degenerated IVDs. Additionally, TNFA stimulation promoted the upregulation of NGF and CGRP in CD14(-) cells. These findings suggested that CD14(+) cells directly and indirectly contributed to inflammatory cytokine and pain-related molecule expression in human degenerated IVD. CD14(+) cells might be important in the pathological mechanism of chronic discogenic LBP in humans.

[Exclusive radiotherapy for a facial basal cell carcinoma with trigeminal ganglion involvement]

Basal cell carcinomas with symptomatic perineural invasion are rare entities. We report the case of a 60year-old man (with a grafted kidney), surgically treated in 2007 for a sclerodermiform basal cell carcinoma infiltrating the left nostril. Five years later, a painful left hemifacial hypoesthesia associated with an ulcus rodens of the nasolabial fold appeared. A biopsy confirmed a recurrence. MRI showed an enhancement of the trigeminal ganglion. The patient had a trigeminal perineural invasion secondary to a cutaneous basal cell carcinoma. He received a local intensity-modulated radiotherapy alone (70Gy in 33 sessions), administered from the skin tumour to the skull base. Three years after the end of treatment, the patient is in radiological and clinical remission, with partial recovery of the hypoesthesia. Evolution was marked by iterative corneal ulcers and decreased visual acuity. Modalities of treatment by surgery and/or radiation therapy and complications are poorly described in the literature.

Molecular Staging of Sentinel Lymph Nodes Identifies Melanoma Patients at Increased Risk of Nodal Recurrence

BACKGROUND

Molecular staging of sentinel lymph nodes (SLNs) may identify patients who are node-negative by standard microscopic staging but are at increased risk for regional nodal recurrence; such patients may benefit from completion lymph node dissection (CLND).

STUDY DESIGN

In a multicenter, randomized clinical trial, patients with tumor-negative SLNs by standard pathology (hematoxylin and eosin [H and E] serial sections and immunohistochemistry [IHC]) underwent reverse transcriptase polymerase chain reaction (PCR) analysis of SLNs for melanoma-specific mRNA. Microscopically negative/PCR+ patients were randomized to observation, CLND, or CLND with high-dose interferon (HDI). For this post-hoc analysis, clinicopathologic features and survival outcomes, including overall survival (OS) and disease-free survival (DFS), were compared between PCR+ patients who underwent CLND vs observation. Microscopic and molecular node-negative (PCR-) patients were included for comparison.

RESULTS

A total of 556 patients were PCR+: 180 underwent observation, and 376 underwent CLND. An additional 908 PCR- patients were observed. Median follow-up was 72 months. Disease-free survival (DFS) was significantly better for PCR+ patients who underwent CLND compared with observation (p = 0.0218). No statistically significant differences in OS or distant disease-free survival (DDFS) were seen. Regional lymph node recurrence-free survival (LNRFS) was improved in PCR+ patients with CLND compared to observation (p = 0.0065). The PCR+ patients in the observation group had the worst DFS; those with CLND had similar DFS to that in the PCR- group (p = 0.9044).

CONCLUSIONS

Patients with microscopically negative/PCR+ SLN have an increased risk of nodal recurrence that was mitigated by CLND. Although CLND did not affect OS, these data suggest that molecular detection of melanoma-specific mRNA in the SLN predicts a greater risk of nodal recurrence and deserves further study.

Probabilistic issues with sentinel lymph nodes in malignant melanoma

OBJECTIVES

To address issues of probability for sentinel lymph node results in melanoma and provide details about the probabilistic nature of the numbers of sentinel nodes as well as to address how these issues relate to tumor thickness and patient outcomes.

METHODS

Analysis of the probability of observing sentinel node metastases uses the discrete exponential probability distribution to address the number of observed positive sentinel nodes. In addition, mathematical functions derived from survival analysis are used. Data are then chosen from the literature to illustrate the approach and to derive results.

RESULTS

Observations about the numbers of positive and negative sentinel nodes closely follow discrete exponential probability distributions, and the relationship between the probability of a positive sentinel node and tumor thickness follows closely a function derived from survival analysis. Sentinel node results relate to tumor thickness as well as to the total number of nodes harvested but fall short of identifying all those who eventually develop metastatic melanoma.

CONCLUSIONS

Probability analyses provide useful insight into the success and failure of the sentinel node biopsy procedure in patients with melanoma.

Lymphatic mapping and sentinel lymph node biopsy in patients with melanoma: a meta-analysis

PURPOSE

To perform a meta-analysis of all published studies of sentinel lymph node (SLN) biopsy for staging patients with melanoma.

METHODS

Published literature in all languages between 1990 and 2009 was critically appraised. Primary outcomes evaluated included the proportion successfully mapped (PSM) and test performance including false-negative rate (FNR), post-test probability negative (PTPN), and positive predictive value in the same nodal basin recurrence.

RESULTS

A total of 71 studies including 25,240 patients met full eligibility criteria. The average PSM was 98.1% (95% CI, 97.3% to 98.6%) and increased with the year of publication, female sex, ulceration, age, and the quality score of the studies. The FNR ranged from 0.0% to 34.0%, averaging 12.5% overall (95% CI, 11% to 14.2%). FNR increased with the length of follow-up (P = .002) but decreased with greater PSM (P = .001). PTPN averaged 3.4% (95% CI, 3.0% to 3.8%), which also increased in studies with longer follow-up, younger age, female sex, deeper Breslow thickness, and with tumor ulceration while decreasing with greater PSM (P < .001). Approximately 20% of the patients with a positive SLN had additional lymph nodes in the complete lymph node dissection and 7.5% of the patients with positive SLN developed recurrence in the same nodal basin which was greater in studies that also reported higher FNR (P = .01).

CONCLUSION

The estimated risk of nodal recurrence after a negative SLN biopsy was ≤ 5% supporting the use of this technology for staging patients with melanoma.

Increased detection of metastatic melanoma in pediatric sentinel lymph node biopsies using RT-PCR on paraffin-embedded tissue

Sentinel lymph node (SLN) biopsy has become integral in the staging of patients with melanoma, and entails detailed histologic examination with immunohistochemistry. Reverse transcriptase-polymerase chain reaction (RT-PCR) for tyrosinase transcripts has been used to increase sensitivity but requires a dedicated piece of tissue that does not undergo histologic examination. We developed a nested RT-PCR assay for tyrosinase applicable on paraffin-embedded tissue and applied this to a series of SLNs from pediatric patients with melanoma. Thirty-six SLNs from 4 females and 4 males were included in the study. Eight lymph nodes with reactive changes were included as controls. SLNs were examined histologically and immunohistochemically for S100, tyrosinase, and MART1. Seven patients had between 1 and 4 morphologically-positive SLNs and one patient had negative SLNs (HISTO+; 12/36, 33%). Three lymph nodes were excluded from molecular analysis owing to inadequate RNA, and 29 of the remaining 33 nodes were positive (MOL+; 88%). All patients had at least 1 SLN positive by RT-PCR. Twelve were HISTO+/MOL+; 17 were HISTO-/MOL+; and 4 were HISTO-/MOL-. All control lymph nodes were negative for tyrosinase transcripts. The application of RT-PCR for tyrosinase to paraffin-embedded tissue significantly increased the number of positive SLNs and upstaged one patient from negative to positive. The prognostic implications of such findings require further investigation, especially in the pediatric age group. Nonetheless, this technique provides a useful tool to determine the clinical significance of RT-PCR positivity in melanoma SLNs.

Prognostic value of tyrosinase reverse transcriptase PCR analysis in melanoma sentinel lymph nodes: long-term follow-up analysis

OBJECTIVE

To determine the prognostic value of detecting tyrosinase transcripts in melanoma sentinel lymph nodes (SLNs).

METHODS

Reverse transcription (RT) PCR for tyrosinase mRNA was performed on negative SLNs of 76 patients with melanoma.

RESULTS

Tyrosinase mRNA was found in 39 patients (51.3%). After a median follow-up period of 51 months, significant differences were found in overall survival (OS) but not in disease-free survival (DFS). The 5-year OS and DFS rates were 97.2% and 80%, respectively, for RT-PCR tyrosinase-negative (TN) patients vs. 78.67% and 66.24% for RT-PCR tyrosinase-positive (TP) patients (P = 0.019 and P = 0.38, respectively). Of four progressing patients in the TN group, three relapsed with subcutaneous, soft-tissue or lymph-node metastases, while seven out of nine progressing patients in the TP group relapsed at visceral sites.

CONCLUSIONS

No significant differences in DFS were found by RT-PCR tyrosinase expression analysis at melanoma SLNs. Significant differences in OS could be related to a different pattern of relapse and must be confirmed after a longer follow-up time.

Molecular staging of pathologically negative sentinel lymph nodes from melanoma patients using multimarker, quantitative real-time rt-PCR

The aim of this study was to evaluate the prognostic potential of quantitative reverse-transcription, polymerase chain reaction (qRT-PCR) in melanoma patients with pathologically negative sentinel lymph nodes (SLN). Our study included 195 node-negative melanoma patients with a Breslow thickness greater than 0.76 mm (n = 158), or less than 0.76 mm but who had Clark level IV-V, microscopic ulceration, or pathological signs of regression (n = 32), and five patients with melanoma of unknown thickness. SLNs were examined by serial-section histopathology. A portion of each SLN was frozen for qRT-PCR analysis using markers Tyrosinase, MART1, SSX2, MAGEA3, PAX3, and GalNAc-T. In addition, two other markers (PLAB and L1CAM) were evaluated for melanoma specificity but not for SLN analysis. Median follow-up was 64 months, during which time there were 15 (7.7%) recurrences. A total of 370 lymph nodes were analyzed by qRT-PCR. No association was found between quantitative expression level of any marker and disease recurrence. Previously published primer designs were tested for PAX3 and GalNAc-T and revealed that alternative PAX3 transcripts are differentially expressed in melanoma and benign lymph nodes. No associations with recurrence were found regardless of the transcripts amplified by different primer sets. PLAB and L1CAM did not appear to differentiate between malignant melanoma and benign melanocytes or lymph nodes in our analysis. We conclude that, in this large cohort of patients, multimarker qRT-PCR analysis of SLNs did not correlate with disease recurrence. Our data support specific PAX3 splice variants but not GalNAc-T, PLAB or L1CAM as possible markers for melanoma metastasis to SLNs.

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.

Sentinel lymph node biopsy in melanoma: a micromorphometric study relating to prognosis and completion lymph node dissection

BACKGROUND

Sentinel lymph node (SLN) positivity has been found to be strongly associated with a poor prognosis in melanoma.

OBJECTIVES

This large referral centre study was conducted: (i) to confirm the powerful prognostic value of SLN biopsy (SLNB); (ii) to correlate patient prognosis to the micromorphometric features of SLN metastasis in SLN-positive patients; and (iii) to correlate these micromorphometric features to the likelihood of positive completion lymph node dissection (CLND).

PATIENTS AND METHODS

SLNB was performed in 455 cases of primary melanoma between January 1999 and December 2004; for patients with positive SLN, the following micromorphometric features were registered: size of the largest metastasis (two diameters), depth of metastasis, number of millimetric slices involved, maximum number of metastases on a single section, presence of intracapsular lymphatic invasion and extracapsular spread. Kaplan-Meier survival curves were compared with the log-rank test; multivariate analysis was performed using a Cox regression model. Dependence of CLND status on micromorphometric features of SLN was assessed by the chi(2) test and predictive values of the different features were evaluated by multivariate analysis using a logistic regression model.

RESULTS

A positive SLN was identified in 98 of our 455 cases. Survival was significantly shorter in SLN-positive patients than in SLN-negative patients. Extracapsular invasion was found to be an independent prognostic factor of disease-free survival; ulceration of the primary and the maximum diameter of the largest metastasis were identified as independent predictive factors of disease-specific survival. Age and the lowest diameter of the largest metastasis were identified as independent predictive criteria of positive CLND, whereas depth of metastasis was not. Positivity of CLND was not significantly associated with a worse prognosis.

CONCLUSIONS

Our study confirms the previously demonstrated strong prognostic value of SLNB. It also confirms the relationship between tumour burden in the SLN (evaluated by the maximum diameter of the largest metastasis) and clinical outcome. We point out a new micromorphometric feature of SLN, which seems to be predictive of CLND status: the lowest diameter of the largest metastasis.

Sentinel lymph node molecular ultrastaging in patients with melanoma: a systematic review and meta-analysis of prognosis

PURPOSE

Molecular biology-based ultrastaging of cancer is already part of the standard management of patients with hematologic malignancies, whereas the evidence for solid tumors is much more debated. Polymerase chain reaction (PCR) -based detection of melanoma cells in sentinel lymph nodes (SLN) of patients with melanoma represents an appealing prognostic tool. However, no consensus exists on the clinical implementation of this prognostic indicator for the management of these patients.

METHODS

Twenty-two studies enrolling 4,019 patients who underwent SLN biopsy for clinical stage I to II cutaneous melanoma were reviewed. Correlation of PCR status with TNM stage, disease recurrence rates, and survival was assessed by means of association statistics and formal meta-analysis, respectively.

RESULTS

PCR status correlated with both TNM stage (stage I to II v III; PCR positivity, 95.1% v 46.6%; P < .0001) and disease recurrence (PCR positive v negative; relapse rate, 16.8% v 8.7%; P < .0001). PCR positivity was also associated with worse overall (hazard ratio [HR], 5.08; 95% CI, 1.83 to 14.08; P = .002) and disease-free (HR, 3.41; 95% CI, 1.86 to 6.24; P < .0001) survival. Statistical heterogeneity was significant, underscoring the variability among overall effect estimates across studies; metaregression and subgroup analysis did not identify clear-cut sources of heterogeneity, although some study design variables were suggested as potential causes.

CONCLUSION

PCR status of SLN appears to have a clinically valuable prognostic power in patients with melanoma. Although the heterogeneity of the studies so far published warrants caution to avoid overestimating the favorable results of pooled data, our findings strongly support additional investigation in this field.

Detection of tyrosinase mRNA in the sentinel lymph nodes of melanoma patients is not a predictor of short-term disease recurrence

Sentinel lymph node evaluation has enabled identification of patients with cutaneous melanoma who might benefit from elective regional lymph node dissection. Sentinel nodes are currently assessed by histologic and reverse transcription polymerase chain reaction (RT-PCR) evaluation for melanocyte-specific markers. The clinical significance of positive findings by RT-PCR in the absence of histologic evidence of metastasis (HIS(NEG)/PCR(POS)) remains unclear. Examination of 264 lymph nodes from 139 patients revealed histopathologic positivity in 34 patients (24.5%), in which 26 also demonstrated simultaneous RT-PCR positivity (HIS(POS)/PCR(POS)). Of 35 HIS(NEG)/PCR(POS) patients (25.2%), five also had nodal capsular nevi. In total, capsular nevi were detected in 13 patients (9.4%). A total of 70 patients (50.4%) had negative sentinel nodes by both histopathology and RT-PCR (HIS(NEG)/PCR(NEG)). Over a median follow-up of 25 months, local and/or systemic recurrence developed in 31 patients (22.3%). Recurrence rates were similar among patients with histopathologic evidence of sentinel lymph node metastasis, irrespective of RT-PCR status (HIS(POS)/PCR(POS) 62%; HIS(POS)/PCR(NEG) 75%). In contrast, only 10% of HIS(NEG)/PCR(NEG) patients developed recurrence, significantly less than those in either HIS(POS) group (P<0.0001). Recurrence in the HIS(NEG)/PCR(POS)/CN(NEG) group (7.7%) was comparable to that in HIS(NEG)/PCR(NEG) patients and significantly lower than that in either HIS(POS) group (P<0.0001). The only independent prognostic factors identified by multivariate analysis were the Breslow thickness of the primary tumour and histopathologic positivity of sentinel nodes. Our findings support previous observations that histopathologic evidence of metastatic melanoma in sentinel lymph nodes is an independent predictor of disease recurrence. In contrast, detection of tyrosinase mRNA by RT-PCR alone does not appear to increase the likelihood of short-term disease recurrence.

Diagnosis and treatment of cutaneous melanoma: state of the art 2006*

Although the incidence of melanoma is still rising in Caucasian populations, the increase in mortality has leveled off. Improvements in early diagnosis, with more frequent diagnosis of low-risk patients (i.e. those with <1 mm of tumor thickness), is the main reason for these divergent developments. Primary prevention has not yet been successful and recent studies have demonstrated the lack of effectiveness of sunscreen in preventing nevi in children. Progress was made in early melanoma diagnosis when dermoscopy and digital dermoscopy were introduced, and computer algorithms have proved to be highly efficacious for automated melanoma diagnosis. Primary melanomas are now excised with narrower surgical margins of 1-2 cm. Sentinel-node biopsy is recommended as a nodal staging procedure in patients with tumor thickness of 1 mm and more, but the prognostic impact of this procedure has not yet been demonstrated. New imaging techniques, e.g. whole-body MRI and PET-CT, provide more accurate staging, particularly in patients with apparent metastasis, and facilitate decisions on surgical treatment strategies. Staging is now based on the 2001 TNM classification including tumor thickness and histopathologic ulceration in stages I and II and lymph node micro and macro-metastasis in stage III. A stage- and risk-adopted follow-up schedule is proposed for melanoma surveillance. Adjuvant therapy with interferon-alpha in high-risk patients offers a small benefit in terms of recurrence-free and overall survival; the optimal dosage and duration of this treatment are still to be defined. Almost no progress has been made in the medical treatment of disseminated metastasis of melanoma. Therapy with dacarbazine and a few other single agents remains the first-line treatment approach of choice. A number of new treatment modalities, including targeted molecules and immunologic approaches with monoclonal antibodies, are under development; hopefully, new treatment modalities will be available in the near future.

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.

“Bak (and Bax) to the Future” — of Primary Melanoma Prognosis?

Bcl-2 proteins either block or activate the "intrinsic" mitochondrial apoptosis pathway. Loss of expression of proapoptotic Bcl-2 proteins, namely Bax and Bak, in primary melanomas is associated with a worse long-term prognosis. Consequently, inactivation of mitochondrial signaling pathways of apoptosis may not only be a prerequisite for melanoma progression but may also hamper therapeutic efforts with chemotherapeutic drugs.

Molecular staging of the sentinel lymph node in melanoma patients: correlation with clinical outcome

BACKGROUND

This study was designed to determine the debated prognostic significance of reverse transcriptase-polymerase chain reaction (RT-PCR) positivity in melanoma patients' sentinel lymph node (SLN) negative by conventional histopathology (PATH).

PATIENTS AND METHODS

Patients with primary stage I-II cutaneous melanoma underwent radioguided sentinel lymphadenectomy. Their SLNs were assessed for tyrosinase (Tyr) and melanoma antigens recognized by T-cells (MART-1) mRNA expression using RT-PCR, in parallel with hematoxylin and eosin staining and immunohistochemistry. Tyr and MART-1 expression in the SLNs were correlated with PATH assay results, standard prognostic factors, time to progression and overall survival.

RESULTS

Twenty-three of the 124 patients (18.5%) had positive SLNs by both PATH and RT-PCR (PATH+/PCR+). Sixteen patients (13%) were negative by PATH and positive by RT-PCR (PATH-/PCR+). Eighty-five patients (68.5%) had SLNs that were negative by both PATH and RT-PCR (PATH-/PCR-). At a median follow-up of 30 months, recurrence rates among the three cohorts were statistically different (PATH+/PCR+, 60%; PATH-/PCR+, 31%; PATH-/PCR-, 9.4%). Seven of 23 (30%) and two of 16 (12.5%) patients died in the PATH+/PCR+ and PATH-/PCR+ SLN groups, respectively, whereas no patient died in the PATH-/PCR- SLN group.

CONCLUSIONS

RT-PCR is more sensitive than PATH to detect SLN metastases and it is a reliable predictor of disease relapse in stage I-II melanoma patients.

Molecular classification of melanoma using real-time quantitative reverse transcriptase-polymerase chain reaction

BACKGROUND

The early detection and characterization of metastatic melanoma are important for prognosis and management of the disease. Molecular methods are more sensitive in detecting occult lymph node metastases compared with standard histopathology and are reported to have utility in clinical diagnostics.

METHODS

Using real-time quantitative reverse transcriptase-polymerase chain reaction ([q]RT-PCR), the authors examined 36 samples (30 melanomas, 4 benign nevi, and 2 reactive lymph nodes) for the expression of 20 melanoma-related genes that function in cell growth and differentiation (epidermal growth factor receptor [EGFR], WNT5A, BRAF, FOS, JUN, MATP, and TMP1), cell proliferation (KI-67, TOP2A, BUB1, BIRC5, and STK6), melanoma progression (CD63, MAGEA3, and GALGT), and melanin synthesis (TYR, MLANA, SILV, PAX3, and MITF). In addition, samples were tested for mutations in BRAF (exons 11 and 15) and NRAS (exons 2 and 3).

RESULTS

Hierarchical clustering analysis of the expression data was able to distinguish between the melanoma and nonmelanoma samples and further stratified the melanoma samples into two groups differentiated by high expression of the genes involved in beta-catenin activation (EGFR and WNT5A) and the MAPK/ERK pathway (BRAF, FOS, and JUN). Eighteen of the 28 patients (64%) were found to have mutations in either exon 15 of BRAF (V599 substitution) or codon 61 of NRAS. The mutations were mutually exclusive and did not appear to be associated with the different expression subtypes.

CONCLUSIONS

The results of the current study demonstrate that real-time qRT-PCR can be analyzed using hierarchical clustering to identify expression patterns that differentiate between melanomas and other tissue types. Using a supervised analysis of the data, the authors found that the best discriminators for molecularly distinguishing between melanoma, benign nevi, and lymph nodes were MLANA, CD63, and BUB1. These markers could have diagnostic utility for the detection of melanoma micrometastasis in sentinel lymph nodes.

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.