Immunohistochemical detection of high-affinity nerve growth factor receptor in neuroblastoma

Immunohistochemical detection of p140trkA and p75LNGFR neurotrophin receptors in neuroblastoma

In neuroblastoma, high levels of mRNA for p140trkA and p75LNGFR neurotrophin receptors are predictive of favorable outcome. Their evaluation by Northern blot, however, requires substantial amounts of tissue and this prevents their routine evaluation as well as the possibility for multicenter studies to be easily carried out. In an attempt to overcome these limitations, the feasibility and reliability of determining both neurotrophin receptors on cryostat sections by immunohistochemistry were assessed, and these findings were compared to those obtained from Northern blot analysis. Primary tumor samples from 28 untreated patients at all stages were evaluated by using H10 anti-p140trkA and ME20.4 anti-p75LNGFR mAbs. Although weak, positive immunostaining was found in 9 of 28 tumors for p140trkA and in 5 of 28 tumors for p75LNGFR. As compared to Northern blot, the concordance rate was 79% (22 of 28 cases) for p140trkA (p < 0.05) and 71% (20 of 28 cases) for p75LNGFR (p < 0.05). No case negative for Northern blot was found to be positive with immunohistochemistry. Since only high mRNA levels for both receptors have been shown to be clinically relevant, their immunohistochemical detection, although less sensitive than Northern blot, can be just as sufficient and reliable as a prognostic tool, and possibly with a better cost-benefit ratio.

Comparison of the diagnostic and prognostic value of biological markers in neuroblastoma. Proposal for a common methodology of analysis. SENSE group

BACKGROUND

The prognosis of pediatric neuroblastoma depends both on clinical presentation and on certain cellular and molecular characteristics. Screening programs have been initiated in infants of less than one year of age, based on the hypothesis that neuroblastoma progresses from early to late clinical stages through a classical multistep process linked to an accumulation of molecular abnormalities. However, recent analyses suggest that most cases discovered by screening are low stage tumors considered as dysembryogenetic residues devoid from major abnormalities and that high-grade tumors with molecular abnormalities are unrelated diseases.

AIM OF THE REVIEW

To confirm one or the other hypothesis, and eventually identify biological factors possibly responsible for the initiation and progression of the disease, it is of utmost importance that all investigators agree on biological criteria for analysis when neuroblastoma tissue is available in screened and unscreened populations. This paper reviews the biological tools available for prognosis in neuroblastoma, the priority for analysis of biological markers according to both methodological reliability and feasibility, and the conditions of tissue storage for further analysis of these biological markers.

CONCLUSION

The standardized biological evaluation of neuroblastoma will allow to collect sufficient data for multivariate analysis; such analysis is now fundamental if one wants to clearly define the respective impacts of biological abnormalities on neuroblastoma progression.