A systematic review of molecular and biological tumor markers in neuroblastoma

High expressions of neuronatin isoforms in favorable neuroblastoma

Neuroblastoma is a malignant solid tumor of children, which derives from the embryonal sympathoadrenal linage. Clinical cases can vary widely from a favorable to an unfavorable prognosis according to the presence of genetic aberrations, such as MYCN amplification. Our cDNA microarray analysis which compared the gene expressions between favorable and unfavorable neuroblastomas showed a high expression of the neuronatin (Nnat) gene in favorable neuroblastomas. Nnat is highly conserved in mammalian species, and its expression appears in nervous systems from the hindbrain to the peripherals during the prenatal periods. The Nnat mRNA expression, investigated in 63 of neuroblastoma samples by quantitative reverse-transcription polymerase chain reaction, was found to be significantly higher in the favorable prognosis groups than in the unfavorable groups. Nnat is an imprinted gene, and its expression in IMR32 neuroblastoma cell line was up-regulated by treatment with a demethylating agent. High expressions of Nnat isoforms induced in an IMR32 neuroblastoma cell line changed the cell morphology to the extension of the neural processes, which thus indicated the occurrence of cell differentiation. In conclusion, the high expressions of Nnat were found to be associated with good prognoses in neuroblastoma, which might indicate tumor differentiation, and its suppressions in unfavorable tumors are considered to be under epigenetic control.

An alternative model for bivariate random-effects meta-analysis when the within-study correlations are unknown

Multivariate meta-analysis models can be used to synthesize multiple, correlated endpoints such as overall and disease-free survival. A hierarchical framework for multivariate random-effects meta-analysis includes both within-study and between-study correlation. The within-study correlations are assumed known, but they are usually unavailable, which limits the multivariate approach in practice. In this paper, we consider synthesis of 2 correlated endpoints and propose an alternative model for bivariate random-effects meta-analysis (BRMA). This model maintains the individual weighting of each study in the analysis but includes only one overall correlation parameter, rho, which removes the need to know the within-study correlations. Further, the only data needed to fit the model are those required for a separate univariate random-effects meta-analysis (URMA) of each endpoint, currently the common approach in practice. This makes the alternative model immediately applicable to a wide variety of evidence synthesis situations, including studies of prognosis and surrogate outcomes. We examine the performance of the alternative model through analytic assessment, a realistic simulation study, and application to data sets from the literature. Our results show that, unless rho is very close to 1 or -1, the alternative model produces appropriate pooled estimates with little bias that (i) are very similar to those from a fully hierarchical BRMA model where the within-study correlations are known and (ii) have better statistical properties than those from separate URMAs, especially given missing data. The alternative model is also less prone to estimation at parameter space boundaries than the fully hierarchical model and thus may be preferred even when the within-study correlations are known. It also suitably estimates a function of the pooled estimates and their correlation; however, it only provides an approximate indication of the between-study variation. The alternative model greatly facilitates the utilization of correlation in meta-analysis and should allow an increased application of BRMA in practice.

Comparative proteomic expression profile in all-trans retinoic acid differentiated neuroblastoma cell line

Neuroblastoma (NB) is an infant tumor which frequently differentiates into neurons. We used two-dimensional differential in-gel electrophoresis (2D-DIGE) to analyze the cytosolic and nuclear protein expression patterns of LAN-5 cells following neuronal differentiating agent all-trans-retinoic acid treatment. We identified several candidate proteins, from which G beta2 and Prefoldin 3 may have a role on NB development. These results strength the use of proteomics to discover new putative protein targets in cancer.

Microvessel density as a prognostic factor in non-small-cell lung carcinoma: a meta-analysis of individual patient data

BACKGROUND

Angiogenesis is a potential prognostic factor that has been investigated in patients with non-small-cell lung carcinoma. However, published studies of the role of angiogenesis as a prognostic factor are inconclusive. We aimed to collect individual patient data to assess microvessel-density counts (ie, a measure of angiogenesis) as a prognostic factor in non-small-cell lung carcinoma.

METHODS

We obtained published and unpublished datasets and extracted appropriate data, taking particular care to ensure data quality. Detailed information was obtained for the laboratory methods used by every research centre that generated the data. The outcome of interest was overall survival. We did a meta-analysis to estimate the prognostic role of microvessel density by combining separately estimated hazard ratios (HR) from every study, which were adjusted for tumour stage and age. Analyses were done separately for studies that used the Chalkley method or for those that counted all microvessels.

FINDINGS

17 centres provided data for 3200 patients, 2719 of which were included in the analysis. All but three centres (datasets 9, 10, and 13-367 cases) had already published their findings, and six had updated follow-up information (datasets 1, 2, 3, 6, 7, and 8-1273 cases). For all but three centres (datasets 4, 11, and 13) some data corrections were necessary. For microvessel density counts obtained by the Chalkley method, the HR for death per extra microvessel was 1.05 (95% CI 1.01-1.09, p=0.03) when analysed as a continuous variable. For microvessel density counts obtained by the all vessels method, the HR for death per ten extra microvessels was 1.03 (0.97-1.09, p=0.3) when analysed as a continuous variable.

INTERPRETATION

Microvessel density does not seem to be a prognostic factor in patients with non-metastatic surgically treated non-small-cell lung carcinoma. This conclusion contradicts the results of a meta-analysis of published data only. Therefore, the methodology used to assess prognostic factors should be assessed carefully.

An evaluation of bivariate random-effects meta-analysis for the joint synthesis of two correlated outcomes

Often multiple outcomes are of interest in each study identified by a systematic review, and in this situation a separate univariate meta-analysis is usually applied to synthesize the evidence for each outcome independently; an alternative approach is a single multivariate meta-analysis model that utilizes any correlation between outcomes and obtains all the pooled estimates jointly. Surprisingly, multivariate meta-analysis is rarely considered in practice, so in this paper we illustrate the benefits and limitations of the approach to provide helpful insight for practitioners. We compare a bivariate random-effects meta-analysis (BRMA) to two independent univariate random-effects meta-analyses (URMA), and show how and why a BRMA is able to 'borrow strength' across outcomes. Then, on application to two examples in healthcare, we show: (i) given complete data for both outcomes in each study, BRMA is likely to produce individual pooled estimates with very similar standard errors to those from URMA; (ii) given some studies where one of the outcomes is missing at random, the 'borrowing of strength' is likely to allow BRMA to produce individual pooled estimates with noticeably smaller standard errors than those from URMA; (iii) for either complete data or missing data, BRMA will produce a more appropriate standard error of the pooled difference between outcomes as it incorporates their correlation, which is not possible using URMA; and (iv) despite its advantages, BRMA may often not be possible due to the difficulty in obtaining the within-study correlations required to fit the model. Bivariate meta-regression and further research priorities are also discussed.

Role of chemotherapy resistance genes in outcome of neuroblastoma

BACKGROUND

Neuroblastoma is a heterogeneous pediatric disease. Most patients with localized disease usually have a favorable prognosis, but patients with advanced disease have a poor prognosis despite combination chemotherapy. Treatment failure may be attributable to resistance to cytotoxic drugs.

PROCEDURE

Using quantitative RT-PCR, we investigated the clinical significance of the level of mRNA expression of multidrug resistance genes (MDR1, MRP1, MRP5, LRP) in a series of 29 advanced neuroblastoma samples.

RESULTS

At the end of induction chemotherapy, 48% of patients achieved a clinical complete response, 28% achieved a partial response or stable disease, and 24% presented progressive disease. MDR1 mRNA overexpression (i.e., mRNA level >2 copies of MDR1 gene) was observed in 74% of samples, and MRP1, MRP5, LRP overexpression was observed less frequently (30, 33, and 33% of samples, respectively). None of these parameters were predictive of response, relapse, or survival. However, clinical response to treatment was highly predictive of relapse-free survival and overall survival.

CONCLUSIONS

High expression of these multidrug resistance genes in advanced neuroblastoma is not the main parameter of response to cytotoxic drugs; clinical response to treatment remains the most important parameter in predicting the prognosis of patients with advanced neuroblastoma, until other relevant laboratory parameters have been identified.

Insulin-like growth factors control cell migration in health and disease

Insulin-like growth factors I and II (IGF-I and IGF-II) have an ancient origin and play essential roles in fundamental biological processes. Although IGFs are principally known for their roles in regulating cell growth and survival, their ability to influence cell motility is just as significant. In the past 20 years, research has provided indisputable evidence for the regulatory role of IGFs in the migration of various cell types. Cell migration is crucial for reproduction, development, and tissue regeneration; IGFs play an important role in coordinating these processes. Moreover, studies continue to uncover the IGFs' role in stimulating cancer cell migration, invasion and metastasis. This review surveys current knowledge on the cell migration-modulating properties of IGFs and the biochemical pathways by which these peptides regulate cell movement in both physiological and pathological conditions.

Peripheral blood stem cell tumor cell contamination and survival of neuroblastoma patients

PURPOSE

Contribution of peripheral blood stem cell (PBSC) contaminating tumor cells to subsequent relapse and overall survival of neuroblastoma patients remains controversial.

EXPERIMENTAL DESIGN

Neuroblastoma cell contamination of 27 PBSC harvests from stage IV neuroblastoma patients was assessed by quantitative RT-PCR for both tyrosine hydroxylase (TH) and GD2 synthase (GD2-s). The effect of PBSC contamination on survival was then analyzed.

RESULTS

Seven PBSC tested negative for both markers; 19 were positive for GD2-s, 6 for TH, with 5 positive for both. Survival of the 20 patients with positive PBSC did not differ from that of the patients with negative PBSC (log-rank test, P = 0.134 and 0.218 for event-free survival and overall survival, respectively). By considering the TH and GD2-s results independently, a borderline (P = 0.053) negative effect on event-free survival was observed in patients reinfused with GD2-s-positive PBSC. When the status at transplant was taken into account, only the event-free survival of the patients rescued when in complete remission with GD2-s-negative PBSC was better, although not significantly, than that of patients infused with GD2-s-positive PBSC.

CONCLUSIONS

Our results obtained in a small cohort of homogeneously treated stage IV patients suggest that patient survival is not affected by PBSC contamination with the exception of a borderline negative effect on event-free survival in patients rescued when in complete remission.

Telomere length is a prognostic factor in neuroblastoma

BACKGROUND

Maintenance of telomeres, in most instances by reactivation of telomerase, is obligatory for the indefinite proliferation of tumor cells. The objective of this study was to evaluate telomere length and telomerase activity (TA) as markers for progression and prognosis in neuroblastoma.

METHODS

Primary tumor samples from 51 patients were analyzed for telomere length and TA and were correlated with known prognostic parameters and outcome.

RESULTS

Telomere length had a highly significant correlation with prognosis (P = .007). Short telomeres were predictive of a favorable prognosis, whereas long or unchanged telomeres were predictive of a poor outcome. For the first time to their knowledge, the authors have shown that, within the high-risk group patients, telomere length could define a favorable subgroup that had a progression-free survival (PFS) rate of 86% compared with a PFS rate of 36% for patients with more adverse disease, which is the expected PFS rate for such patients (P = .04). In a multivariate analysis, telomere length was the most significant prognostic parameter (P = .032). TA was correlated significantly with outcome and with known prognostic factors. High TA and low TA were associated with adverse and favorable outcomes, respectively (P = .01).

CONCLUSION

The results of this investigation suggested that telomere length is a highly significant prognostic parameter of clinical relevance in patients with neuroblastoma. In high-risk patients, telomere length was the sole significant parameter that identified a group of patients who had a favorable prognosis. The authors suggest that telomere length should be included in the recommended diagnostic investigations for patients with neuroblastoma.

Immunotherapy of human neuroblastoma using umbilical cord blood-derived effector cells

Tumors of the nervous system, including neuroblastoma and glioblastoma, are difficult to treat with current therapies. Despite the advances in cancer therapeutics, the outcomes in these patients remain poor and, therefore, new modalities are required. Recent literature demonstrates that cytotoxic effector cells can effectively kill tumors of the nervous system. In addition, we have previously shown that umbilical cord blood (UCB) contains precursors of antitumor cytotoxic effector cells. Therefore, to evaluate the antitumor potential of UCB-derived effector cells, studies were designed to compare the in vitro and in vivo antitumor effects of UCB- and peripheral blood (PB)-derived antigen-nonspecific and antigen-specific effector cells against tumors of the nervous system. Mononuclear cells (MNCs) from UCB were used to generate both interleukin-2 (IL-2)-activated killer (LAK) cells and tumor-specific cytotoxic T lymphocytes (CTLs). UCB-derived LAK cells showed a significant in vitro cytotoxicity against IMR-32, SK-NMC, and U-87 human neuroblastoma and glioblastoma, respectively. In addition, the CTLs generated using dendritic cells primed with IMR-32 tumor cell lysate showed a selective cytotoxicity in vitro against IMR-32 cells, but not against U-87 or MDA-231 cells. Furthermore, treatment of SCID mice bearing IMR-32 neuroblastoma with tumor-specific CTLs resulted in a significant (p < 0.01) inhibition of tumor growth and increased overall survival. Thus, these results demonstrate the potential of UCB-derived effector cells against human neuroblastoma and warrant further preclinical studies.

Diagnostic identification of malignant cells in the cerebrospinal fluid by tumor-specific qRT-PCR

Tumor specific quantitative RT-PCRs for two neuroblastoma specific molecular markers, tyrosine hydroxylase (TH) and GD2 synthase, were used to unequivocally demonstrate the neoplastic nature of the cells present in the cerebrospinal fluid of a neuroblastoma patient. After radical surgery of two separate tumoral lesions, localized in the extradural area, the patient presented with meningitis. Common sites of neuroblastoma metastatization, e.g. bone and bone marrow, were not infiltrated by tumor cells, as assessed by standard scintigraphy, morphological investigation and by sensitive and specific immunocytochemical and molecular assays. The results presented here demonstrate the successful use of tumor-specific qRT-PCRs in cerebrospinal fluid to investigate questionable clinical cases. The technique, which compared to other detection methods (e.g., immunocytochemistry) requires very few cells, yields unambiguous information once a suspected diagnosis has been formulated and a tumor-specific molecular marker is available.

REporting recommendations for tumor MARKer prognostic studies (REMARK)

Despite years of research and hundreds of reports on tumor markers in oncology, the number of markers that have emerged as clinically useful is pitifully small. Often initially reported studies of a marker show great promise, but subsequent studies on the same or related markers yield inconsistent conclusions or stand in direct contradiction to the promising results. It is imperative that we attempt to understand the reasons that multiple studies of the same marker lead to differing conclusions. A variety of methodologic problems have been cited to explain these discrepancies. Unfortunately, many tumor marker studies have not been reported in a rigorous fashion, and published articles often lack sufficient information to allow adequate assessment of the quality of the study or the generalizability of study results. The development of guidelines for the reporting of tumor marker studies was a major recommendation of the National Cancer Institute-European Organisation for Research and Treatment of Cancer (NCI-EORTC) First International Meeting on Cancer Diagnostics in 2000. As for the successful CONSORT initiative for randomized trials and for the STARD statement for diagnostic studies, we suggest guidelines to provide relevant information about the study design, pre-planned hypotheses, patient and specimen characteristics, assay methods, and statistical analysis methods. In addition, the guidelines suggest helpful presentations of data and important elements to include in discussions. The goal of these guidelines is to encourage transparent and complete reporting so that the relevant information will be available to others to help them to judge the usefulness of the data and understand the context in which the conclusions apply.

Effects of hemolysis and storage condition on neuron-specific enolase (NSE) in cerebrospinal fluid and serum: implications in clinical practice

The concentration of neuron-specific enolase (NSE) in serum and cerebrospinal fluid (CSF) has been used as a biomarker in some cancers and, more recently, in neurodegenerative diseases. Pre-analytical conditions are very important for the quality of returned results. In this study, we evaluated the effects of storage conditions (temperature and duration of storage) and hemolysis on the concentration of NSE in serum and CSF. Our results demonstrate that samples for NSE measurement may be stored at -80 degrees C for no more than 6 months in the case of CSF and 9 months in the case of serum samples. Even invisible hemolysis may increase NSE levels in samples. Consequently, an index of hemolysis should be determined before deciding whether or not to perform NSE measurement.

Successful treatment of MYCN amplified, progressive stage 4S neuroblastoma in a neonate with hepatic artery embolization in addition to multimodality treatment

Stage 4S metastatic neuroblastoma (NB) has a favorable prognosis due to a high rate of spontaneous regression. Young infants risk lethal complications arising from hepatomegaly, which can develop rapidly despite treatment. MYCN oncogene amplification confers a significantly worse prognosis. We describe a 4-week-old neonate with MYCN-amplified stage 4S NB complicated by gross hepatomegaly causing rapidly progressive respiratory, hepatic, and renal failure. The child remains in remission 3 years after hepatic artery embolization, radiotherapy, standard, and high-dose chemotherapy. Embolization of the hepatic artery, with classical treatment, is feasible and safe at this age and may contribute substantially to the management of high-risk patients.

Long-term outcomes in patients with stage IV neuroblastoma

AIM OF STUDY

Long-term outcome studies in survivors with stage IV neuroblastoma (NB) are sparse. This review evaluates late complications and long-term outcomes in stage IV NB survivors.

METHODS

A retrospective review of stage IV NB survivors was performed to analyze outcomes, including long-term morbidity, recurrence, and survival.

MAIN RESULTS

Of 153 patients with stage IV NB, 52 (34%) survived (male-female, 26:26). Age at diagnosis was 29.1 +/- 31.7 months in survivors. Eighteen were 1 year or younger and 34 were older than 1 year compared with 10 nonsurvivors 1 year or younger and 91 older than 1 year (P = .0003, Fisher's Exact test). Primary tumor sites were adrenal (35), retroperitoneal (11), mediastinal (3), pelvic (2), and no primary with tumor metastases identified (1). Ten survivors had favorable and 16 had unfavorable histology compared with 1 favorable and 18 unfavorable in nonsurvivors (P = .01). Four survivors had MYCN amplification (> or = 10 copies) and 2 deletions of 1p and 11q. Sites of metastasis in survivors and nonsurvivors were similar. Treatment in survivors included surgery in 51 (75% [39/51] complete tumor resection [CTR]); chemotherapy, 50; radiation, 17; stem cell transplantation, 20; and bone marrow transplant, 1. In nonsurvivors, 13 (25%) of 53 (P < < .0001) had CTR, 18 stem cell transplantation, and 12 bone marrow transplant. Six patients had tumor recurrence but survived (mean, 9.3 +/- 8.3 years; range, 6 months-24 years). Recurrence was local (1), distant (2), and both (3) and was treated by resection, chemotherapy, and radiation. The mean age of survivors was 12.4 +/- 8.3 years (range, 2-34 years). In all stage IV cases, event-free survival was 30% and overall survival was 34%. Long-term complications occurred in 23 (44%) survivors, including endocrine disturbances (7), orthopedic (5), cataracts (2), adhesive bowel obstruction (2), hypertension (1), bronchiolitis (1), blindness (1), peripheral neuropathy (1), nonfunctioning kidney (1), cholelithiasis (1), and thyroid nodule (1).

CONCLUSION

Only 34% of patients with stage IV NB survived despite aggressive multimodal therapy. Age of younger than 1 year, favorable pathology, CTR, and no recurrence were the only statistically significant factors that favored survival. Forty-four percent of survivors experienced late morbidity, and tumor recurred in 6 (11.5%) of 52. Patients should be monitored for tumor recurrence and long-term sequelae. New methods of treatment are required to achieve better outcomes.

The Influence of Biologic Factors on the Surgical Decision in Advanced Neuroblastoma

BACKGROUND

Molecular markers greatly affect the outcome of neuroblastoma. This study evaluated the influence of Trk-A and myelocytomatosis viral-related oncogene, neuroblastoma-derived (MYCN) on the role of surgery in advanced neuroblastoma.

METHODS

Ten stage 3 and 35 stage 4 neuroblastoma patients were included. Tumor resection was classified into gross total resection (GTR) and incomplete resection. Patients were classified into three biological risk groups according to Trk-A expression and myelocytomatosis viral-related oncogene, neuroblastoma-derived (MYCN) status in tumor tissues studied by immunohistochemistry and fluorescence in situ hybridization, respectively: low risk (positive Trk-A and normal MYCN), intermediate risk (negative Trk-A and normal MYCN), and high risk (positive or negative Trk-A and MYCN amplification). The effect of tumor resection on prognosis was studied and stratified according to the risk grouping.

RESULTS

GTR was achieved in 21 patients (46.7%) with a higher complication rate (33% vs. 8% in the incomplete resection group, P = .036). GTR was easier to achieve in low-risk tumors than in intermediate- or high-risk tumors (12 of 13, 4 of 17, and 5 of 15, respectively; P < .001). GTR predicted a favorable prognosis for intermediate-risk patients (P = .037; log-rank test), but not for low- or high-risk patients because of the overall favorable and poor prognosis, respectively.

CONCLUSIONS

GTR carries a potentially higher possibility of complication. Although GTR can be achieved easily in low-risk neuroblastoma patients with a favorable prognosis, surgeons should do their best to achieve GTR for intermediate-risk patients to improve outcome. Nevertheless, sacrificing vital organs to achieve GTR for high-risk patients is not justified.

Telomerase inhibition, telomere shortening, cell growth suppression and induction of apoptosis by telomestatin in childhood neuroblastoma cells

Neuroblastoma is a tumour derived from primitive cells of the sympathetic nervous system and is the most common extracranial solid tumour in childhood. Unfavourable tumours are characterised not only by structural changes, including 1p deletion and amplification of the MYCN proto-oncogene, but also by high telomerase activity. Telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structure, which has been shown to inhibit telomerase activity. In this study, we examined telomestatin, a G-quadruplex interactive agent, for its ability to inhibit telomere maintenance of neuroblastoma cells. Telomere length was determined by the terminal restriction fragment method, telomerase activity was measured by a quantitative telomeric repeat amplification protocol, and the expression of human telomerase by quantitative real-time polymerase chain reaction (RT-PCR). Short-term treatment with telomestatin resulted in dose-dependent cytotoxicity and induction of apoptosis. Long-term treatment with telomestatin at non-cytotoxic, but still telomerase activity-inhibiting, concentrations resulted in telomere shortening, growth arrest and induction of apoptosis. These results suggest that the effect of telomestatin is dose-dependent and at least 2-fold. Prolonged low-dose treatment with telomestatin limits the cellular lifespan of NB cells through disruption of telomere maintenance.

Estudios de precisión diagnóstica (STARD) y pronóstica (REMARK)

Deficiencies in how research studies are reported are both well-documented and widespread across all medical specialties and study designs. Although randomised trials have received the most attention in this regard, similar concerns have been expressed about reporting of other types of research including diagnostic and epidemiological studies. If a journal article describes in enough detail what was done at each stage of a study, readers will have enough information to allow them to decide on the merits of the results for themselves. From this simple idea comes the scientific rationale of developing guidelines on how to report research. Recommended processes to produce reporting guidelines have evolved over several years during the preparation of a sequence of reporting guidelines starting with CONSORT and QUOROM in the 1990s. We describe initiatives to develop reporting guidelines for diagnostic accuracy studies (STARD) and tumour marker prognostic studies (REMARK).

Primer: an evidence-based approach to prognostic markers

Prognostic markers can help to identify patients at different degrees of risk for specific outcomes, facilitate treatment choice, and aid patient counseling. Compared with other research designs, prognostic studies have been relatively neglected in the broad efforts to improve the quality of medical research, despite their ubiquity. Large protocol-driven, prospective studies are the ideal, with clear, unbiased reporting of the methods used and the results obtained. Unfortunately, published prognostic studies rarely meet such standards, and in this article we discuss their main problems and how they can be improved. In particular, an evidence-based approach to prognostic markers is required, as it is usually difficult to ascertain the benefit of a marker from single studies and a clear view is only likely to emerge from looking across multiple studies. Current systematic reviews and meta-analyses often fail to provide clear evidence-based answers, and rather only draw attention to the paucity of good-quality evidence. Prospectively planned pooled analyses of high-quality studies, along with general availability of individual patient data and adherence to reporting guidelines, would help alleviate many of these problems.

Tumor cell dynamics and metastasis in advanced neuroblastoma

This study deals with the advancement process of neuroblastoma through clinical observations and circulating tumor cell exploration. Clinical feature, tumor biology, and circulating tumor cell detected by the previously described polymerase chain reaction (PCR) method were analyzed in 31 patients with advanced neuroblastoma treated in our department since 1991 through 2004. Treatment was completed in 28 patients, of whom 17 are alive without the disease and 11 died. The primary lesion was not confirmed in 2 patients with disseminated metastasis, both of whom showed positive circulating tumor cell. Circulating tumor cell was positive in 6 of 9 examined at their first appearance at the hospital, all had stage 4 disease, and 4 of the 6 (66.7%) died of systemic spread of the disease. N-myc was amplified in 15 patients, of whom only 2 (13.3%) died of systemic metastasis. N-myc amplification did not correlate with positive circulating tumor cell. A certain population of neuroblastoma may provide circulating tumor cells from the early period of the disease to form metastatic lesions independently of the primary lesion, which must be regulated by factors other than N-myc. Circulating tumor cells may suggest higher risk for systemic dissemination and poor prognosis.

REporting recommendations for tumour MARKer prognostic studies (REMARK)

Despite years of research and hundreds of reports on tumour markers in oncology, the number of markers that have emerged as clinically useful is pitifully small. Often initially reported studies of a marker show great promise, but subsequent studies on the same or related markers yield inconsistent conclusions or stand in direct contradiction to the promising results. It is imperative that we attempt to understand the reasons that multiple studies of the same marker lead to differing conclusions. A variety of methodologic problems have been cited to explain these discrepancies. Unfortunately, many tumour marker studies have not been reported in a rigorous fashion, and published articles often lack sufficient information to allow adequate assessment of the quality of the study or the generalisability of study results. The development of guidelines for the reporting of tumour marker studies was a major recommendation of the National Cancer Institute-European Organisation for Research and Treatment of Cancer (NCI-EORTC) First International Meeting on Cancer Diagnostics in 2000. As for the successful CONSORT initiative for randomised trials and for the STARD statement for diagnostic studies, we suggest guidelines to provide relevant information about the study design, pre-planned hypotheses, patient and specimen characteristics, assay methods, and statistical analysis methods. In addition, the guidelines suggest helpful presentations of data and important elements to include in discussions. The goal of these guidelines is to encourage transparent and complete reporting so that the relevant information will be available to others to help them to judge the usefulness of the data and understand the context in which the conclusions apply.

REporting recommendations for tumour MARKer prognostic studies (REMARK)

Despite years of research and hundreds of reports on tumour markers in oncology, the number of markers that have emerged as clinically useful is pitifully small. Often initially reported studies of a marker show great promise, but subsequent studies on the same or related markers yield inconsistent conclusions or stand in direct contradiction to the promising results. It is imperative that we attempt to understand the reasons that multiple studies of the same marker lead to differing conclusions. A variety of methodological problems have been cited to explain these discrepancies. Unfortunately, many tumour marker studies have not been reported in a rigorous fashion, and published articles often lack sufficient information to allow adequate assessment of the quality of the study or the generalisability of the study results. The development of guidelines for the reporting of tumour marker studies was a major recommendation of the US National Cancer Institute and the European Organisation for Research and Treatment of Cancer (NCI-EORTC) First International Meeting on Cancer Diagnostics in 2000. Similar to the successful CONSORT initiative for randomised trials and the STARD statement for diagnostic studies, we suggest guidelines to provide relevant information about the study design, preplanned hypotheses, patient and specimen characteristics, assay methods, and statistical analysis methods. In addition, the guidelines suggest helpful presentations of data and important elements to include in discussions. The goal of these guidelines is to encourage transparent and complete reporting so that the relevant information will be available to others to help them to judge the usefulness of the data and understand the context in which the conclusions apply.

Serological protein profiling of neuroblastoma by ProteinChip SELDI-TOF technology

Serological proteins of neuroblastoma were profiled and analyzed by ProteinChip-SELDI-TOF MS technology with five types of protein chips. By comparing with normal control, a number of protein or polypeptide signals were found significantly and consistently different in their intensities (expression levels) in tumor sera. Interestingly, nine polypeptide peaks in these proteomic features can be simultaneously detected with consistent variations by more than one type of protein chips. None of the expression differences of these nine polypeptides was found in similar comparisons between healthy controls and hepatomas. Preliminary protein identification showed hints for that some of these proteomic alterations may be closely related to the tumorigenesis of neuroblastoma. These results demonstrated the potential of serological biomarker identification for neuroblastoma by ProteinChip-SELDI technology.

Reporting Recommendations for Tumor Marker Prognostic Studies (REMARK)

Despite years of research and hundreds of reports on tumor markers in oncology, the number of markers that have emerged as clinically useful is pitifully small. Often, initially reported studies of a marker show great promise, but subsequent studies on the same or related markers yield inconsistent conclusions or stand in direct contradiction to the promising results. It is imperative that we attempt to understand the reasons that multiple studies of the same marker lead to differing conclusions. A variety of methodologic problems have been cited to explain these discrepancies. Unfortunately, many tumor marker studies have not been reported in a rigorous fashion, and published articles often lack sufficient information to allow adequate assessment of the quality of the study or the generalizability of study results. The development of guidelines for the reporting of tumor marker studies was a major recommendation of the National Cancer Institute-European Organisation for Research and Treatment of Cancer (NCI-EORTC) First International Meeting on Cancer Diagnostics in 2000. As for the successful CONSORT initiative for randomized trials and for the STARD statement for diagnostic studies, we suggest guidelines to provide relevant information about the study design, preplanned hypotheses, patient and specimen characteristics, assay methods, and statistical analysis methods. In addition, the guidelines suggest helpful presentations of data and important elements to include in discussions. The goal of these guidelines is to encourage transparent and complete reporting so that the relevant information will be available to others to help them to judge the usefulness of the data and understand the context in which the conclusions apply.

Selective reporting biases in cancer prognostic factor studies

BACKGROUND

Nonreported and selectively reported information and the use of different definitions may introduce biases in the literature of prognostic factors. We probed these biases in a meta-analysis of a prognostic factor for head and neck squamous cell cancer (HNSCC) mortality that has drawn wide attention--the status of the tumor suppressor protein TP53.

METHODS

We compared results of meta-analyses that included published data plus unpublished data retrieved from investigators; published data; and only published data indexed with "survival" or "mortality" in MEDLINE/EMBASE, with or without standardized definitions. We also evaluated whether previously published meta-analyses on mortality predictors for various malignancies addressed issues of retrieval and standardized information. All statistical tests were two-sided.

RESULTS

For the 18 studies with 1364 patients that included published and indexed data, we obtained a highly statistically significant association between TP53 status and mortality. When we used the definitions preferred by each publication, the association was stronger (risk ratio [RR] = 1.38, 95% confidence interval [CI] = 1.13 to 1.67; P = .001) than when we standardized definitions (RR = 1.27, 95% CI = 1.06 to 1.53; P = .011). The addition of 13 studies with 1028 subjects that included published but not indexed data reduced the observed association (RR = 1.23, 95% CI = 1.03 to 1.47; P = .02). Finally, when we obtained data from investigators (11 studies with 996 patients) and analyzed it with all other data, statistical significance was lost (RR = 1.16, 95% CI = 0.99 to 1.35; P = .06). Among 18 published meta-analyses of 37 cancer prognostic factors, 13 (72%) did not use standardized definitions and 16 (89%) did not retrieve additional information.

CONCLUSIONS

Selective reporting may spuriously inflate the importance of postulated prognostic factors for various malignancies. We recommend that meta-analyses thereof should maximize retrieval of information and standardize definitions.

Multiple numerical chromosome aberrations in cancer: what are their causes and what are their consequences?

Several neoplastic tumor types are cytogenetically characterized by multiple numerical chromosome abnormalities without concomitant structural karyotypic changes. At present, no good gene-level theories are at hand to explain the pathogenetic effect of these changes during tumorigenesis, nor is it known how they arise or what causes them. Genetic instability is often invoked as an underlying cause, but actual data favoring this explanation are meager or non-existing. Numerical chromosome changes and ploidy shifts allow the simultaneous alteration of multiple cancer-relevant genes, thereby reducing the number of independent genomic events necessary for carcinogenesis and the need for postulating genomic instability as a necessity in cancer development.

P53 abnormalities and outcomes in colorectal cancer: a systematic review

We performed a systematic review of studies that investigated the effect of abnormalities of the tumour suppressor gene p53 upon prognosis in patients with colorectal cancer. The methods used to assess p53 status were immunohistochemistry (IHC), indicating abnormal accumulation of p53, and sequence analysis, indicating presence of p53 mutations (mut). We identified 168 reports, with 241 comparisons of relevant end points and survival data on 18 766 patients. We found evidence of both publication bias and heterogeneity of results. Our analysis was hampered by variability in both the assessment of p53 status and the reporting of results. We used a trim and fill method to correct for publication bias and minimised heterogeneity by using well-defined clinical subgroups for the assessment of outcomes. Overall, patients with abnormal p53 were at increased risk of death: relative risk (RR) with IHC 1.32 (95% confidence interval (c.i.) 1.23–1.42) and with mutation analysis 1.31 (95% c.i. 1.19–1.45). The adverse impact of abnormal p53 was greater in patients with lower baseline risk of dying: good prognosis RR (mut) 1.63 (95% c.i. 1.40–1.90) and poor prognosis RR (mut) 1.04 (95% c.i. 0.91–1.19). We found no effect of abnormal p53 on outcome in patients treated with chemotherapy. Abnormal p53 was associated with failure of response to radiotherapy in patients with rectal cancer: RR (mut) 1.49 (95% c.i. 1.25–1.77).

The Doublecortin Gene, A New Molecular Marker to Detect Minimal Residual Disease in Neuroblastoma

Neuroblastoma (NB) is a pediatric cancer of highly variable clinical outcome. Much effort is devoted to detection of minimal residual (MRD) disease through RT-PCR or immunology of tissue-specific markers. Tyrosine hyrdroxylase (TH) has demonstrated a high utility to assess disease dissemination, although this marker can be lost due to clonal variability. Here we propose the use of the doublecortin (DCX) gene as a new molecular marker of neuroblastoma cells. DCX specifically appears in migrating neurons of the central and peripheral nervous system and interacts with and regulates the microtobule cytoskeleton. We have studied this gene by real-time quantitative RT-PCR in a total of 47 primary tumors and 202 samples of bone marrow or peripheral blood from 34 high-risk neuroblastoma patients as well as in 41 normal controls. The expression of DCX demonstrated a good specificity and concordance with TH, showing a higher expression rate in all the sample types studied as well as at different time points from diagnosis. We conclude that DCX would be a more efficient marker of minimal disease in neuroblastoma and perhaps other tumors of neuronal lineage.

Profiling of nuclear extract proteins from human neuroblastoma cell lines: the search for fingerprints

PURPOSE

Neuroblastoma (NB) commonly presents with advanced disease at diagnosis and is associated with poor survival. If identified early, however, survival is improved suggesting a benefit of early detection. The authors have used proteomics technology in an attempt to identify novel markers that permit early detection of NB and characterize its molecular makeup.

METHODS

Three different human NB cell lines SK-N-AS, SK-N-DZ, and SK-N-FI were subjected to series of biochemical fractionation steps to extract nuclear proteins. These proteins were analyzed for differential expression by 2-dimensional polyacrylamide gel electrophoresis. Polypeptides of interest were subsequently identified by liquid chromatography-linked tandem mass spectrometry.

RESULTS

Multiple proteins were identified in these human NB cell lines including SET (a ubiquitous nuclear protein), stathmin (a cytosolic signal transduction protein), and grp94 (a heat shock protein). SET is a putative oncogene associated with the chromosomal translocation (6;9) leading to acute undifferentiated leukemia. Stathmin is an oncogene found in greater abundance in leukemic cells compared to nonleukemic cells. A total of 94-kDa glucose-regulated protein has been shown to be protective in human breast cancer cells in vitro and related with the occurrence, differentiation, and progression of human lung cancer. The first protein has not been previously associated with NB.

CONCLUSIONS

The identification of these 3 previously unrecognized cancer-related potential biomarkers in human NB cell lines may prove useful in developing diagnostic tests. The proteomic methodology of 2-dimensional polyacrylamide gel electrophoresis/mass spectrometry also provides an improved opportunity to understand the natural history of NB and develop novel chemotherapeutic agents for this prevalent childhood malignancy with a dismal outcome.