lactoferrin and Fibroma

Lactoferrin (Lf) is an 80-kDa basic glycoprotein, a member of the transferrin family of iron-binding proteins. Lf immunoreactivity has been extensively investigated in many neoplastic tissues. Recently, Lf expression was documented in the osteoblastic lineage of bone-forming tumors as well as in osteoblasts of fetal bone.. Lactoferrin (Lf) immunoexpression was investigated in 30 human cartilage-forming tumors [15 enchondromas, 6 osteochondromas, 3 chondroblastomas (CBL), 3 chondrosarcomas, and 3 chondromyxoid fibromas (CMF)] as well as in human normal bone specimens and cartilaginous tissues obtained at autopsy from 5 adults and 3 fetuses.In addition, the immunohistochemical expression of Ki-67 antigen was analyzed on parallel sections from the same specimens. Quantification of Lf immunoreactivity was performed by using an intensity distribution (ID) score.. Lf immunoexpression with a variable ID score was encountered exclusively in 3 of 3 chondroblastomas and in 3 of 3 chondromyxoid fibromas. Lf immunoreactivity in these tumors, in clear contrast with the Lf absence in enchondromas, osteochondromas, and chondrosarcomas, may suggest a different histogenesis of the former. In agreement with this histogenetic origin, we detected Lf in the chondroblasts and osteoblasts within the fetal tissue, whereas no immunoreactivity was found in the corresponding adult cells. No significant associations were found between the Lf immunoexpression and the Ki 67 LI of the tumors of our series.. The presence of Lf in neoplastic cells of CBL and CMF, as well as in fetal cartilaginous tissue, may reflect a less mature phenotype of these tumors.

Topics: Adolescent; Adult; Aged; Bone and Bones; Bone Neoplasms; Cartilage; Case-Control Studies; Child; Chondroblastoma; Female; Fibroma; Humans; Immunohistochemistry; Ki-67 Antigen; Lactoferrin; Male; Middle Aged; Young Adult

The antitumor effects of the multifunctional iron-binding glycoprotein, lactoferrin (Lf), were investigated. Lf inhibited growth in mice of transplantable solid tumors induced by v-ras transformed fibroblasts and a methylcholanthrene-induced fibrosarcoma. Lf also substantially reduced lung colonization (experimental metastasis) by B16-F10 melanoma cells in syngeneic mice. Iron-saturated and apo-Lf exhibited comparable levels of tumor inhibition and antimetastatic activity. Transferrin, a related iron-binding protein, had no effect on lung colonization. In the B16-F10 system, elimination of natural killer cell activity by pretreatment of mice with anti-asialo GM1 antibody abrogated the effects of Lf, whereas inhibition of macrophage function with silica did not. The results demonstrate a novel activity for Lf and suggest a potentially important role for this molecule in the primary defense against tumorigenesis.

Topics: 3T3 Cells; Animals; Cell Division; Female; Fibroma; Humans; Lactoferrin; Methylcholanthrene; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Tumor Cells, Cultured