Distribution and mRNA expression of insulin-like growth factor system in pulmonary lymphangioleiomyomatosis.
BACKGROUND
Insulin-like growth factors (IGF-1 and IGF-2), the IGF-1 receptor (IGF-1R), and IGF-binding proteins (IGFBPs) are involved in normal pulmonary development and in the pathogenesis of smooth muscle cell tumors.


METHODS
To evaluate the role of the IGF system in lymphangioleiomyomatosis (LAM), we used immunohistochemical and in situ hybridization techniques to characterize the expression of IGF-1, IGF-2, IGF-1R, and IGFBP-2, -4, -5, and -6 in lung tissue from 18 LAM patients.


RESULTS
IGF-1, ICGF-2, IGF-1R, IGFBP-1, IGFBP-2, IGFBP-4, IGFBP-5, and IGFBP-6 were expressed by LAM cells. Reactivity and mRNA expression for IGF-2 were observed in LAM cells and resembled that found in normal smooth muscle cells during pulmonary development as well as in smooth muscle cell tumors. IGFBP-2, IGFBP-4, and IGFBP-6 were associated with spindle-shaped LAM cells, whereas IGFBP-5 was associated mainly with epithelioid LAM cells.


CONCLUSIONS
These findings suggest that the IGFBPs modulate the effects of the IGFs on LAM cells. Thus, the patterns of localization and expression of components of the IGF system in LAM strongly suggest that these agents are involved in the proliferation of LAM cells.
Valencia
J C
JC
Pathology Section, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1518, USA.
Matsui
K
K
Bondy
C
C
Zhou
J
J
Rasmussen
A
A
Cullen
K
K
Yu
Z X
ZX
Moss
J
J
Ferrans
V J
VJ
D000328:Adult; D005260:Female; D012739:Gonadal Steroid Hormones / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D018969:Insulin-Like Growth Factor Binding Proteins / Q000032:analysis* / Q000235:genetics; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000235:genetics; D007335:Insulin-Like Growth Factor II / Q000032:analysis* / Q000235:genetics; D008168:Lung / Q000737:chemistry; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D018192:Lymphangioleiomyomatosis / Q000378:metabolism* / Q000473:pathology; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis*; D017526:Receptor, IGF Type 1 / Q000032:analysis* / Q000235:genetics
D012739:Gonadal Steroid Hormones; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D017526:Receptor, IGF Type 1