Cell Replication and Angiogenesis in Central Nervous System Tumors and Their Relationship with the Expression of Tissue Prolactin and Hyperprolactinemia

This study aimed to assess the effect of intracellular prolactin (ICPRL) and hyperprolactinemia on cell replication, using an immunohistochemical (IHC) technique for Ki-67 and Mcm-2, and angiogenesis, using IHC for endoglin CD-105, in central nervous system (CNS) tumors. This cross-sectional study included 79 cases of surgically excised primary CNS tumors of neuroepithelial origin (41.8% of all cases: 10.2% astrocytomas, 24% glioblastomas and 7.6% oligodendrogliomas) and meningeal origin (58.2% of all cases). Ki-67 and Mcm-2 indexes were calculated as a percentage of marked cells. The medians for Ki-67 and Mcm-2 indexes were significantly lower in meningiomas than in glioblastomas (p < 0.001 for Ki-67 and p < 0.001 for Mcm-2) and oligodendrogliomas (p < 0.001 for Ki-67 and p = 0.02 for Mcm-2). A good correlation was observed between the Ki-67 and Mcm-2 (rS = 0.60) replication markers. There were no significant differences in vascular density between the different histological types. Immunohistochemistry for ICPRL was positive in 45.6% of the tumors. Serum prolactin (PRL) was elevated in 30.6% of the cases. Multiple regression analysis revealed no important correlation of ICPRL and serum PRL on Ki-67 and Mcm-2 indexes or vascular density. The analysis of the combined impact of ICPRL and serum PRL variables revealed a trend towards an increase in microvessel density in tumor tissue and a significant increase in cell replication markers (p = 0.009 for Ki-67 and p = 0.05 for Mcm-2). PRL in tumor tissue may be one of the modulating factors of cell proliferation in the CNS.