Evaluation of morphological/immunohistochemical versus nuclear medicine imaging modalities in detecting metastatic bone and/or marrow deposits in neuroblastoma patients

The role of microscopic bone marrow examination and [123I]MIBG scintigraphy in detection of bone marrow involvement in patients with neuroblastoma

OBJECTIVES

For the detection of bone marrow (BM) metastases in patients with neuroblastoma, microscopic BM examination and [¹²³I]MIBG scintigraphy are advised. The aims of this study were to assess the concordance of [¹²³I]MIBG and microscopic BM examination (aspirate and biopsy) in detecting BM involvement and to compare invasive disease in BM biopsies and aspirates, both at diagnosis and before autologous stem cell collection (ASCC).

METHODS

Fifty-five patients with stage 4 or stage 4S disease were included, and 37 of them received an autologous hematopoietic stem cell transplantation (AHSCT). The concordance rate was measured and paired binary data were analysed by the McNemar test to look for a systematic difference between diagnostic tests.

RESULTS

At diagnosis and before ASCC, we found acceptable concordance rates for [¹²³I]MIBG versus microscopic BM examination (77.1% and 85.3% respectively). Discordant results were found in both directions and at both time points. The concordance rate for biopsy versus aspirate at diagnosis was 80.6%, however, before ASCC a much higher concordance rate between both microscopic examinations was found (94.1%). While none of the aspirates showed neuroblastoma cells before ASCC, two biopsies still showed tumor invasion.

CONCLUSION

For patients with neuroblastoma, a [¹²³I]MIBG scintigraphy and a microscopic examination of BM aspirate and its biopsy should be used as complementary tools in the evaluation of BM involvement, and this both at diagnosis and during treatment (before ASCC).

The role of β-catenin and paired-like homeobox 2B (PHOX2B) expression in neuroblastoma patients; predictive and prognostic value

BACKGROUND

The expression of β-catenin and paired-like homeobox 2B (PHOX2B) expression were assessed in Neuroblastoma (NB) patients as a diagnostic, prognostic and/or predictive markers.

METHODS

Bone marrow (BM) samples of 52 NB patients were assessed for the expression of β-catenin by immunohistochemistry (IHC), and PHOX2B by real time PCR (RT-PCR), compared to 12 healthy normal controls (NC). The data were correlated to the clinic-pathological features of the patients, response to treatment and disease relapse.

RESULTS

β-catenin was expressed in 40 (76.92%) patients (P < .001). While PHOX2B was expressed in 32/52 (61.5%) patients, with a fold change of 0.29 (0.01-40.0, P = .096). β-catenin expression associated significantly with advanced tumor stage, high risk, positive results by MIBG and bone scan (P = .002, P < .001, P = .006, P = .013; respectively). Also it associated significantly with synaptophysin expression in the BM biopsy (P < .001), with a significant concordance (K = 0.519, P < .001). The expression of β-catenin associated significantly with PHOX2B gene expression [28/32 (87.5%), P = .04], and its fold change (P = .027), with a significant measure of agreement (K = 0.297, P = .022). The fold change of PHOX2B gene expression associated significantly with the high risk of the patients (P = .04). Poor response to treatment associated significantly with the expression of neuron specific enolase (NSE), β-catenin and PHOX2B in NB patients (P = .021, P = .019 and P = .040; respectively). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of synaptophysin for the diagnosis of BM metastasis in NB patients were (69%, 65.2%, 71.4%, 62.5%; respectively, P = .024). While with β-catenin (93.1%, 43.5%, 67.5%, 83.3%; respectively, P = .003), and PHOX2B expression (65.5%, 34.5%, 59.4%, 50%; respectively, P = .574).

CONCLUSION

β-Catenin could be used as a sensitive and reliable marker for detection of BM metastasis and also a good predictor for resistance to treatment in NB patients. While, PHOX2B gene expression in BM aspirate could be a marker for high risk patients and poor response to treatment.