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

Unique Genes in Tumor-Positive Sentinel Lymph Nodes Associated with Nonsentinel Lymph Node Metastases in Melanoma

BACKGROUND

Current risk assessment tools to estimate the risk of nonsentinel lymph node metastases after completion lymphadenectomy for a positive sentinel lymph node (SLN) biopsy in cutaneous melanoma are based on clinical and pathologic factors. We identified a novel genetic signature that can predict non-SLN metastases in patients with cutaneous melanoma staged with a SLN biopsy.

METHODS

RNA was collected for tumor-positive SLNs in patients staged by SLN biopsy for cutaneous melanoma. All patients with a tumor-positive SLN biopsy underwent completion lymphadenectomy. A 1:10 case:control series of positive and negative non-SLN patients was analyzed by microarray and quantitative RT-PCR. Candidate differentially expressed genes were validated in a 1:3 case:control separate cohort of positive and negative non-SLN patients.

RESULTS

The 1:10 case:control discovery set consisted of 7 positive non-SLN cases matched to 70 negative non-SLN controls. The cases and controls were similar with regards to important clinicopathologic factors, such as gender, primary tumor site, age, ulceration, and thickness. Microarray and RT-PCR identified six potential differentially expressed genes for validation. In the 40-patient separate validation set, 10 positive non-SLN patients were matched to 30 negative non-SLN controls based on gender, ulceration, age, and thickness. Five of the six genes were differentially expressed. The five gene panel identified patients at low (7.1%) and high risk (66.7%) for non-SLN metastases.

CONCLUSIONS

A novel, non-SLN gene score based on differential expressed genes in a tumor-positive SLN can identify patients at high and low risk for non-SLN metastases.

L1CAM drives oncogenicity in esophageal squamous cell carcinoma by stimulation of ezrin transcription

L1 cell adhesion molecule (L1CAM) is highly expressed in various types of human cancers, displaying yet unknown molecular mechanisms underlying their oncogenic potential. Here, we found that L1CAM expression was significantly increased in esophageal squamous cell carcinoma (ESCC; n = 157) lesions compared with non-cancerous tissues. High tumorous L1CAM expression significantly correlated with reduced overall survival. Experimentally, L1CAM knockdown led to decreased cell growth, migration, and invasiveness in vitro, whereas overexpression of L1CAM showed the opposite effect. In nude mice, L1CAM depletion attenuated tumorigenesis and ability to penetrate the tissues surrounding ESCC cells. Gene set enrichment analysis (GSEA) and SubpathwayMiner analysis on gene expression profiles (microarray data on ESCC tissues, GSE53625; cDNA microarray data on L1CAM-knockdown ESCC cell line, GSE86268) suggested that L1CAM-co-expression genes were related to cell motility, cell proliferation, and regulation of actin cytoskeleton, validating the above experimental findings. Further mechanistical analysis showed that L1CAM upregulated the expression of the cytoskeletal protein ezrin via activating integrin β1/MAPK/ERK/AP1 signaling and thus led to the malignant phenotypes of ESCC cells. Together, our findings suggest that L1CAM may be employed as a valuable prognosis marker and a therapeutic target for ESCC patients and that L1CAM promotes ESCC tumorigenicity by upregulating ezrin expression.

KEY MESSAGES

L1CAM promotes growth and invasiveness of ESCC cells in vitro and in vivo. L1CAM upregulates the expression of ezrin by integrin α5β1/MAPK/ERK/AP1 pathway. Ezrin is a key downstream effector in the L1CAM-promoted malignant phenotypes. High expression levels of both L1CAM and ezrin significantly correlated with reduced overall survival. Nuclear L1CAM is an independent prognosis marker for esophageal squamous cell carcinoma.

Prognostic factors in melanoma patients with tumor-negative sentinel lymph nodes

BACKGROUND

Sentinel lymph node (SLN) biopsy for melanoma results in accurate nodal staging, which guides treatment decisions. Patients with a negative SLN biopsy in general have a favorable prognosis, but certain subsets are at increased risk for recurrence and death. This study aimed to identify risk factors predictive of prognosis in patients with a tumor-negative SLN biopsy for cutaneous melanoma.

METHODS

In this post-hoc analysis of data from a multicenter prospective randomized trial, clinicopathologic data of patients with cutaneous melanoma ≥1.0 mm Breslow thickness and tumor-negative SLN were analyzed. Disease-free survival, overall survival (OS), and local and in-transit recurrence-free survival were compared by Kaplan-Meier analysis. Risk factors for worse survival were identified with Cox proportional hazard models.

RESULTS

This analysis included 1,998 patients with tumor-negative SLN with a median follow-up of 70 months. Ulceration, Breslow thickness, nonextremity tumor location, and age ≥45 years were independent risk factors for worse disease-free survival and OS. Breslow thickness and ulceration were the only factors on multivariate analysis that predicted local and in-transit recurrence-free survival. Estimated 5-year OS rates ranged from 55.5 to 95.4% on the basis of the defined risk factors.

CONCLUSION

There is a wide range of prognosis among patients with tumor-negative SLN. Breslow thickness, ulceration, age, and anatomic location of the primary melanoma are important independent factors predicting survival and recurrence among such patients. These factors can be used to stratify prognosis among patients with tumor-negative SLN to formulate rational long-term follow-up strategies as well as identify high-risk, SLN-negative patients for clinical trials of adjuvant therapy.

Proof-of-concept rare cancers in drug development: the case for rhabdomyosarcoma

Rare diseases typically affect fewer than 200,000 patients annually, yet because thousands of rare diseases exist, the cumulative impact is millions of patients worldwide. Every form of childhood cancer qualifies as a rare disease-including the childhood muscle cancer, rhabdomyosarcoma (RMS). The next few years promise to be an exceptionally good era of opportunity for public-private collaboration for rare and childhood cancers. Not only do certain governmental regulation advantages exist, but these advantages are being made permanent with special incentives for pediatric orphan drug-product development. Coupled with a growing understanding of sarcoma tumor biology, synergy with pharmaceutical muscle disease drug-development programs, and emerging publically available preclinical and clinical tools, the outlook for academic-community-industry partnerships in RMS drug development looks promising.

"Stealth" melanoma cells in histology-negative sentinel lymph nodes

A proportion of patients who develop regional and distant recurrences of melanoma after a pathologically negative sentinel lymph node (SN) biopsy are reported to have enhanced signals for melanoma-associated messenger ribonucleic acid (mRNA) when sensitive molecular approaches such as reverse transcriptase polymerase chain reaction (RT-PCR) are used to evaluate their SN tissue. The significance of these findings remains controversial, because the cellular source of the augmented signals cannot be known as the nodal tissue is destroyed during preparation for RT-PCR. Nevertheless, it is claimed that the source of the augmented signal is covert metastatic melanoma cells. To determine whether there are histologically occult metastases in SN and whether there are sources of augmentable melanoma-associated mRNA other than melanoma cells, we applied reverse transcriptase in situ polymerase chain reaction (RT in situ PCR) to formalin-fixed paraffin-embedded nodal tissue. This approach amplifies small amounts of melanoma-associated mRNA and permits identification of cells that express that mRNA. Cells containing MART-1 mRNA were detected in 6 of 21 SNs (29%) and 2 of 16 nonsentinel lymph node (NSNs) (13%) that were tumor negative on hematoxylin and eosin and on immunohistochemical assessment for S-100, MART-1, and HMB-45. In patients with microscopic evidence of melanoma in their SN, MART-1 mRNA-positive cells were identified in 2 of 7 NSNs (29%) that were histologically tumor free. MART-1 mRNA-positive cells were also detected in tumor-negative SN sections from 6 of 7 (86%) nodes that had tumor present in areas of the node not represented in the studied sections. Some cells that expressed MART-1 mRNA that was diffusely distributed in the cytoplasm appeared to be melanoma cells, whereas others resembled macrophages. The latter cells expressed augmented mRNA on granules that were intermixed with melanin granules. In other cases, MART-1 mRNA-positive macrophage-like cells contained nuclei and nucleoli more typical of melanoma cells and may represent the macrophage-melanoma hybrids that have been previously reported. Combination of RT in situ PCR for MART-1 mRNA and immunohistochemistry for CD68 revealed that CD68 was colocalized in some cells that expressed MART-1 mRNA. Some lymph nodes that are tumor negative by histology and immunohistochemistry contain cells that express mRNA for MART-1. Some of these cells may be interpreted as "stealth" melanoma cells in which, despite the presence of MART-1 mRNA, there is an absence of immunohistochemically detectable MART-1 protein. Other cells that contain MART-1 mRNA are clearly not melanoma cells or may represent melanoma hybrids. These findings should be taken into account when interpreting and applying the results of RT-PCR analysis of nodal (and other) tissues.

Current and planned multicenter trials for patients with primary or metastatic melanoma

Multicenter clinical trials have established new standards of care in the surgical and medical management of malignant melanoma. They have led to the testing of new therapies and improved outcomes for patients with loco-regional and distant disease. Many pressing questions remain, however, and additional multicenter trials are currently underway to address them. The purpose of this review is to summarize relevant ongoing and planned multicenter trials that have and continue to define current melanoma management.

Histopathological diagnostics of malignant melanoma in accordance with the recent AJCC classification 2009: Review of the literature and recommendations for general practice

BACKGROUND

TNM classifications are the basis for diagnostic and therapeutic procedures in oncology. Histopathological reports have to enable a proper indexing of tumor specific findings into recent classifications.

METHODS

A systematic review of the literature was performed to identify reports dealing with the assessment of mitotic rate and the processing and evaluation of sentinel node biopsies in malignant melanoma. On the basis of this review an expert panel of dermatopathologists and general pathologists discussed and agreed recommendations for general practice.

RESULTS

Following recommendations were agreed with a broad consensus (93-100 % agreement): The determination of the mitotic rate in primary melanoma is performed on HE slides. The evaluation of an area of 1 mm(2) is sufficient. Only dermal mitoses are considered. The counted number of mitoses is provided as an integer value. The mitotic rate shall be determined in primary melanomas of ≤1.00 mm vertical tumor thickness according to the hot-spot method and provided as an integer value in relation to an area of 1 mm(2) . The determination of the mitotic rate in the case of thicker primary melanomas is desirable. In general, for the evaluation of each sentinel lymph node, 4 slides should be prepared. For diagnostic purposes, immunohistochemistry (preferably with antibodies against S100ß, Melan A and HMB-45) should be performed in addition to HE staining. The pathology report should provide information about micro-metastases and their longest extension (one-tenth of a millimeter).

CONCLUSIONS

These recommendations are suitable for standardizing the histopathological diagnosis of malignant melanoma and for providing a common basis for clinical decisions and scientific research.

Insights into the Role of PAX-3 in the Development of Melanocytes and Melanoma

Melanoma is the deadliest form of skin cancer in the United States with an increasing prevalence. However, the development of melanoma from a melanocyte precursor is still poorly defined. Understanding the molecules responsible for melanoma progression may lead to improved targeted therapy. One potential molecule is the paired box-3 (PAX-3) protein, which has been implicated in the development of melanocytes and malignant melanoma. In melanoma, the expression of PAX-3 is believed to be differentially regulated, and has been linked with malignancies and staging of the disease. The loss of PAX-3 regulation has also been associated with the loss of transforming growth factor-beta (TGF-β) activity, but its effect on PAX-3 in differentiated melanocytes as well as metastatic melanoma remains unclear. Understanding PAX-3 regulation could potentially shift melanoma to a less aggressive and less metastatic disease. This review summarizes our current knowledge on PAX-3 during melanocyte development, its regulation, and its implications in the development of novel chemo-immunotherapeutics against metastatic melanoma.

Molecular upstaging based on paraffin-embedded sentinel lymph nodes: ten-year follow-up confirms prognostic utility in melanoma patients

OBJECTIVE

To determine the long-term clinical significance of molecular upstaging in histopathology-negative, paraffin-embedded (PE) sentinel lymph nodes (SLNs) from melanoma patients.

BACKGROUND

Histopathologic evaluation can miss clinically relevant melanoma micrometastases in SLNs. This longitudinal correlative study is the first 10-year prognostic evaluation of a multimarker quantitative real-time reverse transcriptase-polymerase chain reaction (qRT) assay for PE melanoma-draining SLNs.

METHODS

The SLN sections (n = 214) were assessed by qRT assay for 4 established messenger RNA biomarkers: MART-1, MAGE-A3, GalNAc-T, and PAX3.

RESULTS

The qRT assay upstaged 48 of 161 histopathology-negative (hematoxylin-eosin and immunohistochemistry) SLN specimens. At a median follow-up of 11.3 years for the entire cohort, estimated rates of 10-year overall survival (OS) and melanoma-specific survival (MSS) were 82% and 94%, respectively, for histopathology-negative/qRT-negative patients; 56% and 61%, respectively, for histopathology-positive patients; and 52% and 60%, respectively, for histopathology-negative/qRT-positive patients (P < 0.001 for OS, P < 0.001 for MSS). In a multivariate analysis of known melanoma prognostic factors, qRT positivity was significant (P < 0.05) for disease-free survival (hazard ratio [HR], 4.3; 95% confidence interval (CI), 2.3-7.8), distant disease-free survival (HR, 6.6; 95% CI, 2.9-14.6), MSS (HR, 6.2; 95% CI, 2.6-14.4), and OS (HR, 2.8; 95% CI, 1.6-4.9).

CONCLUSION

The multimarker qRT assay has prognostic significance for molecular upstaging of PE melanoma-draining SLNs. Molecular upstaging of histopathology-negative SLNs confers a prognosis similar to that associated with SLN micrometastasis, and the number of positive qRT biomarkers is correlated to disease outcome.

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.

Lymphatic mapping and sentinel lymphadenectomy in primary cutaneous melanoma

The management of clinically normal regional lymph nodes in early-stage melanoma has been controversial for over a century. Lymphatic mapping and sentinel lymphadenectomy (LM/SL) has been developed as a minimally invasive surgical technique to stage the regional lymph nodes without the associated morbidity of elective complete lymph node dissection. Multiple retrospective studies have validated the accuracy of LM/SL and the importance of the sentinel nodes as a staging tool for melanoma. Two multicenter, prospective, randomized trials have been performed to validate the data from the Phase II studies and determine if a therapeutic benefit exists for LM/SL.

Significance of sentinel lymph node biopsy in malignant melanoma: overview of international data

The notion of sentinel lymph node (SLN) mapping and its use during surgery for staging cancer was initially reported in 1992, in a study involving patients with malignant melanoma. To date SLN biopsy (SLNB) has emerged as a rational approach for staging regional lymph nodes in patients with clinically node-negative melanoma (stage I and II disease). The significance of SLNB as a staging and prognostic tool in melanoma is widely accepted. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of the SLN remains very controversial. Whether SLNB improves survival in melanoma patients remains an open question.