[Monosomy 1p and alkaline phosphatase in meningiomas. Citopathological, histochemical and genetical study in 10 tumors].

Background: Cytogenetic studies in meningiomas show that 1p monosomy constitutes an important factor involved in their progression. Genes coding for unspecific alkaline phosphatase (AP-un) are located in this chromosome, in particular in 1p34-p36.1. This enzyme is widely distributed in the body and it is also found in meningiomas. The loss of expression of this enzyme in meningiomas has been associated with the presence of 1p monosomy in these tumors.

Patients And Method: We studied 10 meningiomas from 8 patients which shared 1p monosomy. Three tumors had a benign morphologic pattern; it was atypical in two and malignant in five cases. We performed a cytogenetic study and FISH as well as a determination of AP-un in tumor cells.

Results: In 8 of ten cases, a loss of AP-un expression was observed. One case displayed positivity in 20% cells. In a positive case, activity was demonstrated in 80% cells.

Conclusions: Our work aimed at analysing the relationship between loss of expression of AP-un, 1p monosomy and the aggressiveness of meningioma. Our results back the interest in determining this enzyme in tumor cells as a quick method with important prognostic value.