Minimal residual disease in gastric cancer: evidence of an independent prognostic relevance of urokinase receptor expression by disseminated tumor cells in the bone marrow.
OBJECTIVE
To study the invasion-related molecule urokinase-type plasminogen activator receptor (u-PAR) expressed by disseminated tumor cells as a biologic predictor of poor survival in a large prospective series of patients with gastric cancer.


METHODS
In 156 gastric cancer patients (prospective series), disseminated tumor cells in the bone marrow and the u-PAR expressed by these tumor cells were determined by cytokeratin (CK) 18 immunocytochemistry and u-PAR/CK18 double immunocytochemistry.


RESULTS
In contrast to the mere detection of disseminated tumor cells at primary surgery, the additional evidence of u-PAR on these cells correlated significantly with pathologic T stage (P =.0474) and the expression of u-PAR (P =.0093) and plasminogen-activator inhibitor 1 (P =.0145) in the primary tumor (immunohistochemistry, chi(2)). Kaplan-Meier analysis revealed no association with prognosis for the mere detection of disseminated tumor cells. In contrast, a significant association was seen between detection of u-PAR on these cells and shorter disease-free (P <.0001) and overall survival (P <.0001). Multivariate analysis revealed that u-PAR on disseminated tumor cells at the time of primary surgery is an independent prognostic factor for disease-free (95% confidence interval [CI], 1.72 to 3.21; P =.024) and overall survival (P =.0049; relative risk, 2.89; 95% CI, 1.92 to 4.30).


CONCLUSIONS
This is the first large study to show that u-PAR, detected on disseminated tumor cells in the bone marrow, is an independent prognostic parameter in gastric cancer, in contrast to the mere detection of minimal residual disease (MRD). u-PAR may be a promising marker to define a critical subpopulation of disseminated tumor cells and a target to eliminate MRD. Molecular phenotyping of MRD is critical for defining its individual clinical relevance.
Heiss
Markus Maria
MM
Department of Surgery, Klinikum Grosshadern, Ludwig Maximilians University of Munich, Munich, Germany.
Simon
Erich H
EH
Beyer
Bianca C M
BC
Gruetzner
Klaus Uwe
KU
Tarabichi
Anwar
A
Babic
Rudolf
R
Schildberg
Friedrich Wilhelm
FW
Allgayer
Heike
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D019046:Bone Marrow Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000556:secondary*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D018365:Neoplasm, Residual / Q000175:diagnosis; D015849:Plasminogen Inactivators / Q000378:metabolism; D011379:Prognosis; D011446:Prospective Studies; D011956:Receptors, Cell Surface / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D013274:Stomach Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D016019:Survival Analysis; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; C524898:PLAUR protein, human; D015849:Plasminogen Inactivators; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D007633:Keratins; D014568:Urokinase-Type Plasminogen Activator