Malignant effusions contain lysophosphatidic acid (LPA)-like activity.
BACKGROUND
Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are bioactive phospholipids with mitogenic and growth factor-like activities that act via specific cell-surface receptors present in many normal and transformed cell types. LPA has recently been implicated as a growth factor present in ascites of ovarian cancer patients. The presence of LPA-like activity and the hypothesis that levels of this bioactivity in effusions of ovarian cancer patients are higher than those in effusions of other cancer patients was studied.


METHODS
A neurite retraction bioassay in a neuroblastoma cell line previously developed for in vitro detection of LPA activity on cell lines was employed and bioactivity was expressed in virtual LPA-equivalent levels. LPA-equivalent levels were tested in effusions of 62 patients with a range of malignancies, including 13 ovarian cancer patients. Biochemical and clinical parameters were evaluated for correlations with LPA-equivalent levels.


RESULTS
Average LPA-equivalent levels were 50.2 microns (range 5.4-200) for all patients, and 94.5 microns (range 15-200) for ovarian cancer patients (P = 0.004). There were no additional independent significant correlations between LPA-equivalent levels in effusions and a range of other biochemical and clinical characteristics.


CONCLUSIONS
These data suggest a role for LPA-like lipids in the peritoneal spread of ovarian cancer and possibly that of other predominantly intraperitoneal malignancies.
Westermann
A M
AM
Department of Medical Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands. annie@nki.nl
Havik
E
E
Postma
F R
FR
Beijnen
J H
JH
Dalesio
O
O
Moolenaar
W H
WH
Rodenhuis
S
S
D000230:Adenocarcinoma / Q000378:metabolism / Q000556:secondary; D001202:Ascitic Fluid / Q000737:chemistry* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000378:metabolism; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism; D005260:Female; D006258:Head and Neck Neoplasms / Q000378:metabolism; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism; D008113:Liver Neoplasms / Q000556:secondary; D008175:Lung Neoplasms / Q000378:metabolism; D008228:Lymphoma, Non-Hodgkin / Q000378:metabolism; D008246:Lysophospholipids / Q000032:analysis*; D009382:Neoplasms, Unknown Primary / Q000378:metabolism; D010051:Ovarian Neoplasms / Q000378:metabolism* / Q000473:pathology; D016066:Pleural Effusion, Malignant / Q000737:chemistry*; D011379:Prognosis; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
D014408:Biomarkers, Tumor; D008246:Lysophospholipids