ORIGINAL ARTICLE

Identification of growth hormone receptor in localised neurofibromas of patients with neurofibromatosis type 1

K S G Cunha, E P Barboza and E C Da Fonseca

Federal Fluminense University, Medicine School, Pathology Department, Niterói, Rio de Janeiro, Brazil

Correspondence to:
Correspondence to:
Dr K S G Cunha, Rua do Catete, 311/Sala 1314, Catete, Rio de Janeiro, Brazil CEP 22220–001;
karingoncalves{at}terra.com.br

Background: The hallmark of neurofibromatosis type 1 (NF1) is the development of multiple neurofibromas. Solitary neurofibroma may occur in an individual who does not have NF1, but multiple neurofibromas tend to develop only in those with NF1. It has been suggested that hormones may influence the neurofibromas of patients with NF1. The evidence that hormones may influence the growth of neurofibromas comes mainly from the observation that localised neurofibromas of patients with NF1 commonly grow during puberty and pregnancy. Because growth hormone (GH) concentrations increase during puberty, it is possible that GH influences the growth of these tumours.

Aims: To investigate the presence of GH receptors (GHRs) in neurofibromas.

Methods: By means of immunohistochemistry, the presence of GHRs was investigated in two groups of patients: 16 patients without NF1 with solitary neurofibromas (group A) and 10 patients with NF1 with localised neurofibromas (group B).

Results: Six of the 16 patients in group A had neurofibromas that were immunopositive for GHR, whereas nine of the 10 patients in group B were immunopositive.

Conclusions: Most patients with NF1 have localised neurofibromas that express GHR. This suggests that GH may play some role in the development of localised neurofibromas in patients with NF1.

Keywords: growth hormone; growth hormone receptor; neurofibroma; neurofibromatosis

Abbreviations: GAP, GTPase activation protein; GH, growth hormone; GHR, growth hormone receptor; IRS, insulin receptor substrate; MAP, mitogen activated protein; NF1, neurofibromatosis type 1; STAT, signal transducer and activator of transcription

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