Bone marrow examination in neuroblastoma patients: a morphologic, immunocytochemical, and immunohistochemical study

Recommendations for the standardization of bone marrow disease assessment and reporting in children with neuroblastoma on behalf of the International Neuroblastoma Response Criteria Bone Marrow Working Group

BACKGROUND

The current study was conducted to expedite international standardized reporting of bone marrow disease in children with neuroblastoma and to improve equivalence of care.

METHODS

A multidisciplinary International Neuroblastoma Response Criteria Bone Marrow Working Group was convened by the US National Cancer Institute in January 2012 with representation from Europe, North America, and Australia. Practical transferable recommendations to standardize the reporting of bone marrow disease were developed.

RESULTS

To the authors' knowledge, the current study is the first to comprehensively present consensus criteria for the collection, analysis, and reporting of the percentage area of bone marrow parenchyma occupied by tumor cells in trephine-biopsies. The quantitative analysis of neuroblastoma content in bone marrow aspirates by immunocytology and reverse transcriptase-quantitative polymerase chain reaction are revised. The inclusion of paired-like homeobox 2b (PHOX2B) for immunohistochemistry and reverse transcriptase-quantitative polymerase chain reaction is recommended. Recommendations for recording bone marrow response are provided. The authors endorse the quantitative assessment of neuroblastoma cell content in bilateral core needle biopsies-trephines and aspirates in all children with neuroblastoma, with the exception of infants, in whom the evaluation of aspirates alone is advised. It is interesting to note that 5% disease is accepted as an internationally achievable level for disease assessment.

CONCLUSIONS

The quantitative assessment of neuroblastoma cells is recommended to provide data from which evidence-based numerical criteria for the reporting of bone marrow response can be realized. This is particularly important in the minimal disease setting and when neuroblastoma detection in bone marrow is intermittent, where clinical impact has yet to be validated. The wide adoption of these harmonized criteria will enhance the ability to compare outcomes from different trials and facilitate collaborative trial design. Cancer 2017;123:1095-1105. © 2016 American Cancer Society.

Detecting minimal residual disease in neuroblastoma patients-the present state of the art

While cyto- and histological screening of bone marrow samples are still accepted as the gold standard for initial staging of neuroblastoma patients, these applications are insufficient during or after therapy because it is not always possible to detect tumour cell infiltration below the level of 1% by morphology alone. For monitoring of minimal residual disease, techniques offering a considerably higher sensitivity have been developed. Immunocytology, RT-PCR and flow cytometry are most frequently used, but differ with regard to targets (single cells, RNA transcripts), measured parameters (tumour cell number, antigen expression, cytomorphology, cytogenetic aberrations, level/number of RNA transcripts), specificity (uni-/multi-parameter analysis) and sensitivity (number of investigated cells). The pros and cons of these methods are reviewed. Precise quantification of residual tumour cells in bone marrow and blood may show a future impact on risk grouping and therapeutic strategies for patients with disseminated disease, but the potential clinical application of these techniques has to be preceded by thorough standardisation and validation in multi-centre studies.

Lacking immunocytological GD2 expression in neuroblastoma: report of 3 cases

Immunocytological bone marrow assessment for contamination with neuroblastoma cells is based on their characteristic GD2 surface staining. Neuroblastoma without GD2 expression have been rarely and only after antibody therapy reported. Conventional cytology was performed using Pappenheim staining. For immunocytology, the APAAP method was utilized with the 14G2a anti-GD2 mouse monoclonal antibody. 7 x 10(5) cells on cytospin preparations were investigated. In 2003, 288 bone marrow samples from 191 neuroblastoma patients were investigated by cytology and immunocytology. Three cases demonstrated GD2 negativity on cytologically unambiguous neuroblastoma cells. Two female cases (94 and 37 months of age) with stage 4 neuroblastoma had GD2 expressing neuroblastoma cells in bone marrow at diagnosis. At 2nd relapse 25 and 23 months after diagnosis and 8 months and 12 months after anti-GD2 antibody treatment (ch14.18), the bone marrow infiltrating neuroblastoma cells lacked GD2 staining. The third patient, a 63-month-old girl with bone marrow replacement by neuroblastoma cells showed at diagnosis a mixture of GD2-unstained tumor clumps and very weakly stained neuroblastoma cells. Neuroblastoma cells may lack GD2 expression at diagnosis and at recurrence. This observation has diagnostic and therapeutic implications.

Immunocytochemical detection of bone marrow-invasive neuroblastoma cells

We evaluated the utility of an immunocytochemical technique employing the commercially available anti-CD56 monoclonal antibody, NKH 1. The utility and sensitivity of this technique in the detection of invasive neuroblastoma (NB) cells in the bone marrow were compared with those of Wright-Giemsa staining. The correlation coefficient for the percent NB cells detected using Wright-Giemsa staining with the percent NKH 1 immunoreactive cells was 0.78. In the analysis of specificity, this monoclonal antibody showed slight cross-reactivity with normal bone marrow cells, including macrophages, lymphocytes and osteoblasts. In the evaluation of the sensitivity of the NKH 1 immunocytochemical technique, SK-N-DZ and SK-N-SH NB cell lines were added to morphologically normal bone marrow mononuclear cells from patients without NB to the final NB cell line at concentrations of 2%, 1% and 0.1%. NB cells at the final concentration of 0.1% could be detected by the immunocytochemical technique. We conclude that the NKH 1 immunocytochemical staining technique is useful in the detection of metastatic NB cells in bone marrow.

Immunohistochemistry on needle biopsies of childhood malignancies

Ultrasound-guided percutaneous needle biopsy proved to be a reliable and safe method to obtain material for histopathological and immunohistochemical diagnosis prior to treatment in childhood malignancies. A principal tumour identification could be obtained by a combined morphological and phenotypic examination of 38 small-sized tumour biopsy specimens using a fairly limited panel of immunological reagents, including antibodies to leucocyte common antigen (CD 45), certain B- and T-cell markers, various intermediate filaments (cytokeratin, desmin and vimentin), and neuroblastoma cells (UJ 167.11, A2B5, and UJ 13A; the latter recognizes NCAM). Five undifferentiated neuroblastomas were all positive with the neuroblastoma antibodies but negative for the other markers, including vimentin. The negative reactivity for desmin and vimentin was the major immunohistochemical distinction between neuroblastomas and rhabdomyosarcomas. In addition, limited reactivity with the neuroblastoma antibodies was seen in blastematous parts of Wilms' tumour, duct-like structures in a hepatoblastoma, and in tumour cells in a few undifferentiated myelo- and lympho-proliferative lesions. This study shows the importance of a combined evaluation of morphology and the pattern of immunoreactivity employing multiple markers.

Expression of neural cell adhesion molecule (NCAM) isoforms in neuroblastoma

A comparative study on the expression of the neural cell adhesion molecule (NCAM) in human neuroblastoma cell lines and tissues was undertaken. NCAMs are a family of closely related cell surface glycoproteins involved in cell-cell interactions. Using antibodies that recognise distinct epitopes on NCAM, their presence was shown in neuroblastoma, but these studies do not yield any information on the specific NCAM isoforms associated with the tumour. Western and Northern blot analyses were therefore carried out to characterise the NCAM isoforms in this neuroectodermal tumour. Western blot studies using the monoclonal antibody ERIC-1 showed that all human neuroblastoma cell lines tested expressed the 140 and 120 kilodalton isoforms of NCAM in their desialo state. Some of the cell lines also expressed NCAM-180. The data are corroborated by Northern blotting where a transcript of 7.4 kilobase pairs was identified only in lines expressing NCAM-180; the 6.7 and 5.4 kilobase pair transcripts coding for 140 and 120 kilodalton isoforms, respectively, were present in all the cell lines tested. The NCAM isoforms identified in neuroblastoma were also different from those found in adult and fetal brain tissue, suggesting that aberrations are expressed in the molecule during tumorigenesis.

Bone marrow trephine interpretation: diagnostic utility and potential pitfalls

Good quality paraffin-embedded sections can be obtained from bone marrow trephines, allowing the routine use of these biopsies in diagnostic histopathology. Trephines are superior to aspirates, especially for the assessment of marrow cellularity, the extent and pattern of tumour infiltration and the cell type. Bone marrow biopsies are useful in several areas, e.g. non-haematological disorders, myelodysplasia, the myeloproliferative group, lymphomas and leukaemias, which are briefly discussed below. Further advances in interpretation are likely with more frequent use of bone marrow trephines.

Routine histological compared with immunohistological examination of bone marrow trephine biopsy specimens in disseminated neuroblastoma

The ability to detect infiltration in bone marrow biopsy specimens from patients with disseminated neuroblastoma was assessed by immunohistological and routine histological methods. Frozen cores from 33 staging procedures were tested with UJ13A and UJ127.11. Immunopositive tumour cells were found in 10 of 17 staging procedures in which tumour was detectable by routine histological methods. Positive cells or stromal material were also found in eight of 12 staging procedures in which distorted architecture and fibrosis, but no obvious tumour, had been noted. Paraffin wax embedded cores from 29 of the same staging procedures were tested with antibodies against neurone specific enolase and neurofilament. Only a single core reacted with anti-neurofilament antibody. Neurone specific enolase positive cells or stromal material were found in nine of 15 staging procedures in which obvious tumour was detectable. Although these immunohistochemical techniques proved inferior to routine histology in their ability to detect obvious tumour, the demonstration of immunopositive stromal tissue which was not frankly malignant supports the view that distorted, fibrotic marrow may reflect persistence of neuroectodermal tissue and justifies its distinction from normal marrow when reporting the response to treatment.

Prognostic value of immunocytologic detection of bone marrow metastases in neuroblastoma

BACKGROUND

Morphologic evaluation of bone marrow for neuroblastoma cells is a routine and important component of clinical staging. Specific immunostaining of malignant cells with monoclonal antibodies should be more sensitive, however, and may improve the detection of metastases and provide additional prognostic information.

METHODS

We looked for tumor cells in bone marrow from 197 patients with newly diagnosed neuroblastoma, using immunoperoxidase staining with monoclonal antibodies (immunocytologic analysis) and examination of smears and specimens obtained by trephine biopsy (conventional analysis).

RESULTS

Routine smears and trephine-biopsy specimens were positive for tumor cells in 46 percent of the patients, whereas 67 percent were positive on immunocytologic analysis (P less than 0.0001). Immunocytologic analysis detected bone marrow metastases in 34 percent of patients considered to have only localized or regional disease (Stage I, II, or III). It also identified tumor cells that were not detected by conventional analysis in patients with widespread disease (Stage IV or IVS). Tumor content, as determined by immunocytologic analysis, predicted clinical outcome in relation to the age of the patient at diagnosis. Patients with Stage II or III disease diagnosed after one year of age who did not have occult marrow metastases did well, whereas those with metastases did poorly (P = 0.006). Patients in whom Stage IV disease was diagnosed before they were one year of age did well if bone marrow metastases were few or absent, but had poor survival if the marrow contained more than 0.02 percent tumor cells (P = 0.03).

CONCLUSIONS

Immunocytologic analysis of bone marrow aspirates is more sensitive than conventional analysis in detecting tumor cells and provides prognostic information. The relations among marrow metastases, age at diagnosis, and clinical outcome illustrate the biologic heterogeneity of neuroblastoma.

NB84: a new monoclonal antibody for the recognition of neuroblastoma in routinely processed material

A new monoclonal antibody NB84 recognizing an uncharacterized molecule of 57 kD was produced using human neuroblastoma tumour tissue as a source of antigen. The antibody was selected for its ability to give reliable staining on conventional formalin-fixed, paraffin-embedded material. In the present study, NB84 was assessed for its usefulness in the differential diagnosis of paediatric small cell tumours. It gave reliable staining of 17/19 (90 per cent) neuroblastomas and was negative on all other tumours apart from Ewing's sarcomas, of which 9/14 (64 per cent) showed mainly focal positivity. It is concluded that in association with a panel of markers against leucocyte, muscle, epithelial, and neural markers NB84 provides considerable assistance in the recognition of neuroblastoma and thus is important in enabling the most appropriate therapy to be given.

Immunohistochemical detection of neuroblastoma in frozen sections of bone marrow trephine biopsy specimens

Frozen sections from bone marrow trephine biopsy specimens from children with disseminated neuroblastoma were stained using the monoclonal antibody UJ13A. An immunoalkaline phosphatase technique was the preferred staining method. Acceptable histological detail was obtained from this material and deposits of tumour cells detected. Some apparently fibrous tissue was also stained by this antibody. The results show that this immunohistological approach is feasible and provide encouragement for its addition to the range of investigations currently available for assessing the marrows of children with this disease.