title: Increased serum leptin levels and over expression of leptin receptors are associated with the invasion and progression of renal cell carcinoma.
abstract: OBJECTIVE
  Leptin, an adipocyte derived cytokine that is closely associated with obesity, was recently shown to be involved in carcinogenesis and cancer progression. Because obesity is a significant risk factor for renal cell carcinoma, we investigated the link between leptin and the development of renal cell carcinoma.
  
  
  METHODS
  Associations between preoperative serum leptin levels and leptin receptor expression in tumor specimens and various clinicopathological parameters were analyzed in 57 patients with renal cell carcinoma.
  
  
  RESULTS
  Serum leptin levels were 1.2 to 16.2 ng/ml (mean 4.5). Of 57 tumors 22 (38.6%) demonstrated high leptin receptor expression. Serum leptin levels were significantly higher in patients with vs without tumor specimen venous invasion (p = 0.030) and higher in patients with high vs low leptin receptor expression (p = 0.019). There were significant associations between high leptin receptor expression and the presence of venous invasion (p = 0.013), histological type (p = 0.0076) and regional lymph node metastasis (p = 0.047). Of 42 patients with N0M0 disease those with serum leptin 5.0 ng/ml or more had significantly shorter progression-free survival than patients with lower levels (p = 0.0043). Multivariate Cox proportional hazards model analysis demonstrated that higher serum leptin was an independent predictor of progression-free survival (p = 0.0406).
  
  
  CONCLUSIONS
  Leptin and leptin receptor could have a key role in the invasion of renal cell carcinoma and they could be valuable predictors of progression.
authors.affiliation: Department of Urology, National Defense Medical College, Tokorozawa-City, Saitama, Japan. impreza@cb3.so-net.ne.jp
authors.forename: Akio
authors.initials: A
authors.lastname: Horiguchi
authors.forename: Makoto
authors.initials: M
authors.lastname: Sumitomo
authors.forename: Junichi
authors.initials: J
authors.lastname: Asakuma
authors.forename: Takako
authors.initials: T
authors.lastname: Asano
authors.forename: Rong
authors.initials: R
authors.lastname: Zheng
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Asano
authors.forename: David M
authors.initials: DM
authors.lastname: Nanus
authors.forename: Masamichi
authors.initials: M
authors.lastname: Hayakawa
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002292:Carcinoma, Renal Cell / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011956:Receptors, Cell Surface / Q000378:metabolism*; D054411:Receptors, Leptin; D016896:Treatment Outcome
chemical_list: C515448:LEPR protein, human; D020738:Leptin; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin