title: Cystatin C and lactoferrin concentrations in biological fluids as possible prognostic factors in eye tumor development.
abstract: OBJECTIVE
  To investigate the possible role of cystatin C in eye biological fluids locally and in serum and lactoferrin revealing anti-tumor activity in eye tumor development.
  
  
  BACKGROUND
  The increased number of eye tumors was registered recently not only in the countries with high insolation, but also in the northern countries including Russia (11 cases per million of population). Search for new biological markers is important for diagnosis and prognosis in eye tumors. Cystatin C, an endogenous inhibitor of cysteine proteases, plays an important protective role in several tumors. Lactoferrin was shown to express anti-tumor and antiviral activities. It was hypothesized that cystatin C and lactoferrin could serve as possible biomarkers in the diagnosis of malignant and benign eye tumors.
  
  
  METHODS
  A total of 54 patients with choroidal melanoma and benign eye tumors were examined (part of them undergoing surgical treatment). Serum, tear fluid and intraocular fluid samples obtained from the anterior chamber of eyes in patients with choroidal melanoma were studied.
  
  
  METHODS
  Cystatin C concentration in serum and eye biological fluids was measured by commercial ELISA kits for human (BioVendor, Czechia); lactoferrin concentration--by Lactoferrin-strip D 4106 ELISA test systems (Vector-BEST, Novosibirsk Region, Russia).
  
  
  RESULTS
  Cystatin C concentration in serum of healthy persons was significantly higher as compared to tear and intraocular fluids. In patients with choroidal melanoma, increased cystatin C concentration was similar in tear fluid of both the eyes. Lactoferrin level in tear fluid of healthy persons was significantly higher than its serum level. Significantly increased lactoferrin concentration in tear fluid was noted in patients with benign and malignant eye tumors.
  
  
  CONCLUSIONS
  Increased level of cystatin C in tear fluid seems to be a possible diagnostic factor in the eye tumors studied. However, it does not allow us to differentiate between malignant and benign eye tumors. Similar changes were noted for lactoferrin in tear fluid.
authors.affiliation: Institute of Physiology, Siberian Branch of Russian Academy of Medical Sciences, Novosibirsk, Russia.
authors.forename: Mariya A
authors.initials: MA
authors.lastname: Dikovskaya
authors.forename: Alexandr N
authors.initials: AN
authors.lastname: Trunov
authors.forename: Valeriy V
authors.initials: VV
authors.lastname: Chernykh
authors.forename: Tatyana A
authors.initials: TA
authors.lastname: Korolenko
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001082:Aqueous Humor / Q000737:chemistry; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D016022:Case-Control Studies; D002830:Choroid Neoplasms / Q000097:blood / Q000175:diagnosis; D055316:Cystatin C / Q000032:analysis* / Q000097:blood; D005134:Eye Neoplasms / Q000097:blood / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007781:Lactoferrin / Q000032:analysis* / Q000097:blood; D008297:Male; D008545:Melanoma / Q000097:blood / Q000175:diagnosis; D008875:Middle Aged; D013666:Tears / Q000737:chemistry
chemical_list: D015415:Biomarkers; D055316:Cystatin C; D007781:Lactoferrin
keywords: choroidal melanoma; cystatin C; eye biological fluids; lactoferrin; serum; tears