False positive results in a neuroblastoma screening programme

Neuroblastoma-derived secretory protein is a novel secreted factor overexpressed in neuroblastoma

Secreted proteins such as growth factors, cytokines, and chemokines play important roles in tumor development. Through expression microarray and bioinformatic analysis, we discovered a novel secreted protein, neuroblastoma-derived secretory protein (NDSP). The NDSP gene is found on chromosome 1q25.2 and encodes a 167 amino acid protein with a putative signal peptide. Using real-time PCR and immunoblotting, we find that NDSP is specifically overexpressed in neuroblastoma at much higher levels than other adult and pediatric malignancies and normal tissues. NDSP is an 18-kDa protein that can be secreted by NDSP-transfected HEK-293T cells, as well as, neuroblastoma cell lines endogenously expressing NDSP. Inhibiting NDSP expression in neuroblastoma cell lines with retrovirally transduced NDSP small hairpin interfering RNA, sh-NDSP, results in decreased cellular proliferation and colony formation. We also find inhibited extracellular signal-regulated kinase (ERK)1/2 phosphorylation in the sh-NDSP cell line. Treating the parental cell line with MAP/ERK kinase 1/2 inhibitors, which diminish ERK1/2 phosphorylation, results in decreased cell proliferation. Culturing these transduced cells with recombinant NDSP, reintroducing NDSP overexpression in the knockdown cell line, or inducing Ras oncogene overexpression for constitutive ERK1/2 activation results in a reversal of the growth-inhibited phenotype and proliferation rates similar to the control cells. In addition, reintroduction of NDSP overexpression in the sh-NDSP cell line results in ERK1/2 phosphorylation similar to control. We conclude that NDSP is specifically overexpressed in neuroblastoma and actively secreted from tumor cells. Furthermore, NDSP serves as a growth factor for neuroblastoma tumor cells through activation of the ERK-mediated proliferation pathway.

Retroperitoneal hemangioma of infancy

A premature infant presented with an incidental finding of a mass in the retroperitoneum adjacent to the adrenal gland seen on a renal ultrasound study. A clinical diagnosis of neuroblastoma was made based on imaging and laboratory studies; however, upon resection, histological examination revealed a cellular capillary hemangioma of infancy. Hemangioma should be considered in the differential diagnosis of asymptomatic retroperitoneal mass lesions in infants.

Elevated catecholamine metabolites in patients with Costello syndrome

Costello syndrome is a rare congenital anomaly syndrome with a predisposition to specific tumors, including neuroblastoma, rhabdomyosarcoma, and transitional cell carcinoma of the bladder. The increased risk for solid tumors led to the proposal of a tumor screening protocol. A screening test for neuroblastoma consists of measuring catecholamine metabolites in urine, an assay that may also be used for diagnostic confirmation of a suspected catecholamine secreting tumor. We report eight patients with Costello syndrome with elevated catecholamine metabolites, vanillylmandelic acid (VMA) and/or homovanillic acid (HVA), in urine. Each patient had additional laboratory and/or imaging studies. None of the patients was found to have a neuroblastoma or another catecholamine secreting tumor. In two cases, the assays were performed because the patients were symptomatic with diaphoresis and hypertension, respectively, and in the other six cases the assays were performed in order to screen for neuroblastoma. The pathophysiology for the catecholamine metabolite abnormality in these patients with Costello syndrome remains unclear. However, it appears that in this patient group an elevation above the normal limit, defined as 2 standard deviations (SD) above the mean for age, is more likely to be a variant, rather than a sign of a neuroblastoma. Thus, it may be prudent not to use this assay as a screening test, and to take the frequently elevated results into consideration when interpreting diagnostic assays.

False-positive results in neuroblastoma screening: the parents' view

PURPOSE

One of the major problems of any screening program is the occurrence of false-positive results. For neuroblastoma screening, little information is available on the psychological consequences for parents whose children had false-positive results that made further clinical evaluation necessary. It was the aim of this study to evaluate the parents' view by a semistructured interview.

PATIENTS AND METHODS

Among 267,302 infants screened in the Austrian study between 1991 and 1999, 19 had to be considered as repeatedly false-positive (no clinical evidence of neuroblastoma). Sixteen of 19 parent pairs could be reached by phone and were interviewed separately by use of a semistructured questionnaire to evaluate for psychological consequences resulting from the screening result.

RESULTS

The psychological burden appeared to be small during the initial screening procedure, but it increased significantly through hospital admission and was then described as severe by 19 of the 32 parents.

CONCLUSIONS

Investigators should be aware of the psychological consequences of hospital admission for tumor screening in children. In ongoing neuroblastoma screening studies, laboratory methods as well as cutoff limits should be selected carefully.

A 5-year (1990-1994) neuroblastoma screening feasibility study in France. Methodology and preliminary observations

INTRODUCTION

Following the pioneering Japanese experience, several European and North American groups implemented pilot studies on screening infants for neuroblastoma, considering the possibility of demonstrating a decrease in mortality rate. In France, a 5-year (1990-1994) feasibility study on neuroblastoma screening at the age of 4 months was initiated in the Rhône district (1.5 M inhabitants, 26,000 births per year).

METHODS

Vanillylmandelic (VMA) and homovanillic (HVA) acids were measured by HPLC, and creatinine (Cr) by the Jaffé's kinetic method on Technicon RA-XT. VMA and HVA were expressed as microgram/mg of Cr. The method was assessed with both a daily intra-laboratory control and a sample of urine obtained from a national quality control organism.

RESULTS AND DISCUSSION

The overall participation rate for the 5-year period was 82.2%. Out of 105,293 infants tested from 128,126 births, 12 NB cases were discovered with screening (screened cases) and 1 case was discovered with a late performed test (at 13 months of age). Six neuroblastomas were found clinically before the age of 4 m. Two cases were missed because the parents did not perform the test. Three children with normal tests at screening were false-negative cases: two of them were found secreting at diagnosis, while one remained non-secretory at diagnosis and later on. Otherwise, thirty-five false-positive tests were found. Biochemical observations are discussed. It is too early to reach clinical conclusions from this screening program on neuroblastomas as it is presently being followed up.

Screening for neuroblastoma: a 9-year birth cohort-based study in Niigata, Japan

Between April 1985 and March 1994 (9 years), 229,346 babies were born in Niigata prefecture, and 201,888 (88.0%) underwent mass screening (MS) for neuroblastoma at 6 months of age. To date, 29 infants have been screen-detected as having neuroblastoma (1:7908). All screen-detected patients survived after removal of the primary tumor. In the same birth cohort, 17 additional children were clinically diagnosed as having neuroblastoma. The cumulative incidence rate of neuroblastoma at 5 years of age was 10.5 per 100,000 live births in the 5-year birth cohort before MS was introduced, and 18.6 per 100,000 in the first 5-year birth cohort after MS was introduced. These values were not statistically different. The birth cohort incidence rate increased significantly to 22.2 per 100,000 (p < 5% compared with before MS) after the method of MS was changed to high-power liquid chromatography (HPLC), even though this latest birth cohort has not been followed for 5 years. The population-based mortality rate from neuroblastoma was 5.9 per 100,000 in the 5-year birth cohort before MS, and 4.5 per 100,000 after MS in the first 5-year birth cohort, using the vanillymandelic acid (VMA) spot test. These values were not statistically significant. In contrast, no death was observed in the next 4-year birth cohort after MS using HPLC; however, this birth cohort has not yet been followed for 5 years.

Screening infants for neuroblastoma: the parents' perspective in false-positive cases

The objective of this study was to ascertain the reactions and experiences of parents whose children were defined as false-positive cases in a research program of screening 6-month-old babies for neuroblastoma. Parents of seven of the eight infants falling into this category participated in the study. Parents of five children described themselves as worried/very worried at the positive result, some contemplating the treatment involved and the possibility that their child could die. Parents waited a maximum of 3 days before the clinical investigations took place. The mother of one child was dissatisfied with the handling of the investigations, reporting a lack of information and little opportunity to discuss questions; she was subsequently more anxious about her child. Parents of two children reported lasting "concerns" that they attributed to neuroblastoma screening.