The role of steroid hormones in the NF1 phenotype: Focus on pregnancy

Abstract

The Neurofibromatosis Type 1 (NF1) gene functions as a tumor suppressor gene. Loss of its protein, neurofibromin, in the autosomal dominant disorder NF1 is associated with peripheral nervous system tumors, particularly neurofibromas, benign lesions in which the major cell type is the Schwann Cell (SC). Benign and malignant human tumors found in NF1 patients are heterogeneous with respect to their cellular composition. The number and size of neurofibromas in NF1 patients has been shown to increase during pregnancy, with, in some cases, post-partum regression, which suggests hormonal involvement in this increase. However, in this review, we consider evidence from the literature that both direct hormonal influence on tumor growth and on angiogenesis may contribute to these effects.

A Rare Vulvar Manifestation of Neurofibromatosis 1 in a Teen

“…The changing milieu of sex steroids and growth factors during puberty imply that these substances may play a role in neurofibroma growth. Hormonal involvement contributing to growth is also supported by an increase in size and number of neurofibromas during pregnancy 12 and with puberty, as was seen in this case. In an examination of 59 human neurofibroma specimens, progesterone and estrogen receptors were found in 75% and 5% of specimens, respectively, regardless of gender.…”

Evolving Pattern with Age of Cutaneous Signs in Neurofibromatosis Type 1: A Cross-Sectional Study of 728 Patients

“…Cutaneous and subcutaneous NF appear around the age of 8 years [5]. Their number increases with age, and 2 major growth periods are identified – puberty and pregnancy – in the literature [6,7]. In histological studies, receptors of growth or steroid hormones have been described on cutaneous NF, reinforcing their potential role in NF growth [8].…”

Clinical and genetic aspects of neurofibromatosis 1

“…105 Many women with NF1 experience a rapid increase in the number and size of neurofibromas during pregnancy. 106 Large pelvic or genital neurofibromas can complicate delivery, and cesarean section appears to be necessary more often than usual in pregnant women with NF1. Hormonal contraception does not appear to stimulate the growth of neurofibromas in women with NF1.…”