title: Prognostic significance of periodic acid-Schiff-positive patterns in clear cell renal cell carcinoma.
abstract: BACKGROUND
  The ability of aggressive tumors to form nonendothelial tumor cell-lined microvascular channels is known as "vasculogenic mimicry" (VM). VM channels are revealed as periodic acid-Schiff (PAS)-positive patterns, and in some tumors their presence predicts clinical outcomes.
  
  
  OBJECTIVE
  We aimed to study VM channels in clear cell renal cell carcinoma (cRCC) tumors and explore their prognostic significance and relationship to other suggested prognostic factors such as thymidine phosphorylase (TP) and vascular endothelial growth factor (VEGF) expression.
  
  
  METHODS
  We retrospectively studied 45 patients who had undergone radical nephrectomy for clinically confined cRCC (stage T2-T3NOMO) at the Russian Cancer Research Center. The tumor sections were reviewed for disease stage, nuclear grade, perirenal fat invasion, and lymph node involvement, and we performed immunohistochemical staining for VEGF and TP expression, and PAS staining. Disease-free survival probabilities were determined by Kaplan-Meier estimates and prognostic factors were evaluated by univariate analysis.
  
  
  RESULTS
  PAS-positive patterns observed in the cRCC tumor included back-to-back closed loops, networks, arcs, and parallel patterns. There was a significant decrease in disease-free survival among patients with PAS-positive networks (p = 0.005), but not among patients with other PAS-positive patterns. TP expression was also a significant predictor of disease-free survival (p = 0.035), but this factor did not correlate with the presence of PAS-positive networks. Notably, in our small sample, the six patients whose tumors were positive for both factors had the highest risk of cancer recurrence.
  
  
  CONCLUSIONS
  The presence of PAS-positive networks is an independent and relevant prognostic parameter for disease-free survival in patients with cRCC. Our data suggest that the combination of PAS-positive networks and TP expression may identify patients with the highest risk of cancer recurrence.
authors: N.N. Blokhin Russian Cancer Research Center, Russian Academy of Medical Sciences, Moscow, Russia.
authors: Amalia A
authors: AA
authors: Vartanian
authors: Eugenia V
authors: EV
authors: Stepanova
authors: Sergey L
authors: SL
authors: Gutorov
authors: Elico Sh
authors: ESh
authors: Solomko
authors: Irina N
authors: IN
authors: Grigorieva
authors: Irina N
authors: IN
authors: Sokolova
authors: Anatoly Yu
authors: AY
authors: Baryshnikov
authors: Mikhail R
authors: MR
authors: Lichinitser
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000737:chemistry / Q000378:metabolism*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010503:Periodic Acid-Schiff Reaction; D011379:Prognosis; D012189:Retrospective Studies; D013939:Thymidine Phosphorylase / Q000032:analysis; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis
chemical_list: D042461:Vascular Endothelial Growth Factor A; D013939:Thymidine Phosphorylase