Somatostatin anti-proliferative and anti-angiogenic activities, together with the expression of
somatostatin receptors (sstrs), account for the use of
somatostatin analogues in the treatment of human tumours. In the present study,
sstr2A immunohistochemical expression was analyzed in grade II and III
meningiomas and was compared with that revealed in grade I
meningiomas. Thirty-five
formalin-fixed
paraffin-embedded
meningiomas, comprising 13 grade I, 19 grade II and 3 grade III tumours, according to the WHO 2007 classification, were submitted to immunohistochemical assays for
sstr2A. Moreover, in the same cohort of tumours, the immunoexpression of CD105, a specific marker for neo-angiogenesis, as well as the Ki-67 labelling index (LI), reflecting the proliferative activity of the
meningiomas, were recorded.
Sstr2A immunoreaction was evidenced in 26/35 cases and was localized at the cytoplasm and the plasma membrane in 12 and in 14 cases, respectively. Specifically, a positive staining was found in 7/13 grade I, in 16/19 grade II and in 3/3 grade III tumours, thus demonstrating that
sstr2A is frequently expressed in high grade
meningiomas. A significantly higher microvessel density (MVD), assessed by CD105 immunostaining and Ki-67 LI were evidenced in high grade
meningiomas. A significant correlation was recorded between
sstr2A expression and a high MVD of the
meningiomas. The existence of a correlation between
sstr2A expression and the entity of neo-angiogenesis provides the basis for the use of
somatostatin analogue-based
therapies in the treatment of
meningiomas.